- 18:00Registration & Welcome Cocktail
- 19:30End of Registration
- 20:00End of Welcome Cocktail
Optical System Designs II
Small Satellites II
Flight Demonstrations II
Welcome and Plenaries
Flight Demonstrations IV
Flight Demonstrations III
Terrestrial and Space Technologies
Plenary: Pléiades Show
Flight Demonstrations I
Optical System Designs I
Atmospheric Turbulence and Coding Algorithm
Optical Ground Station Technologies
Fiber Optic Component Qualification
(ICSOS/ICSO Joint Session)
Small Satellites I
Poster Session / Tutorials
Shuttle Departure for Conference Dinner
- Welcome and Plenaries
- Welcome & ICSO Conference overview
Bruno Cugny (CNES, France), Nikos Karafolas (ESA, Netherlands) & Errico Armandillo (ESA, Netherlands)
- 09:30CNES Presentation of Preparatory Activities to Optical Instrument Projects
- Bruno Cugny (CNES, France)
- 10:05ICSOS Conference Overview and Activities on Satellite Communications
- Naoto Kadowaki (NICT, Japan)
- Flight Demonstrations I
- Chair:Zoran Sodnik (ESA, The Netherlands)
- 11:101-1[Invited] The Laser Communications Relay Demonstration
- (NASA Goddard Space Flight Center, USA); (NASA Goddard Space Flight Center, USA); (JPL, USA); (MIT Lincoln Laboratory, USA); (MIT Lincoln Laboratory, USA)
- This paper provides an overview of NASA's Laser Communications Relay Demonstration Project (LCRD). LCRD will fly two optical communications terminals on a Loral commercial communications satellite in GEO orbit to communicate with two ground stations. It is a joint project between NASA's Goddard Space Flight Center (GSFC), the Jet Propulsion Laboratory, California Institute of Technology (JPL), and the Massachusetts Institute of Technology Lincoln Laboratory (MIT/LL). LCRD will operate for a minimum of two years in GEO, demonstrating how optical communications can meet NASA's growing need for higher data rates and be a path finder for providing optical services on NASA's Next Generation Tracking and Data Relay Satellite. In addition, the optical communications capability of LCRD will allow it to serve as a developmental testbed. This paper reviews the mission concept and preliminary designs for the flight and ground optical segments, and reports preliminary conclusions from several trade studies conducted.
- 11:351-2[Invited] Recent Developments in Satellite Laser Communications: Canadian Context
- (Neptec Design Group, Canada); (Neptec Design Group, Canada); (Neptec Design Group, Canada); (Canadian Space Agency, Canada); (Canadian Space Agency, Canada); (McMaster University, Canada)
- This paper presents an overview of recent developments to assess feasibility and relevance of satellite laser communication within Canadian context. The following application scenarios will be discussed: LEO - GEO - Ground relay links and LEO - Ground links for high data rate communications, as well as technology application to LEO - Ground links for secure key distribution. Focus will be made on feasibility and architecture of optical downlink including ground receiver as well as on the terrestrial technology demonstrations, the key necessary steps preceding development of laser satellite link missions. The paper will discuss as well the key technology components required for satellite laser communications. A number of prior and on-going mission development activities and technology developments in the area of laser sensors provide space heritage and necessary technology readiness level for those critical elements. These activities will be discussed.
12:001-3[Invited] Overview and Status of the Lunar Laser Communication Demonstration
- (MIT Lincoln Laboratory, USA)
- The Lunar Laser Communication Demonstration (LLCD), a project being undertaken by MIT Lincoln Laboratory, NASA's Goddard Space Flight Center, and the Jet Propulsion Laboratory, will be NASA's first attempt to demonstrate optical communications between a lunar orbiting spacecraft and Earth-based ground receivers. The LLCD space terminal will be flown on the Lunar Atmosphere and Dust Environment Explorer (LADEE) spacecraft, presently scheduled to launch in 2013. LLCD will demonstrate downlink optical communications at rates up to 620 Mbps, uplink optical communications at rates up to 20 Mbps, and two-way time-of-flight measurements with the potential to perform ranging with sub-centimeter accuracy.
- Laser Technologies
- Chair:Keith Wilson (JPL, USA)
- 14:002-13-Year-Program of 10W-Class Space-Borne Q-sw Laser Technology: Development of Entry Model for Earth Observation
- (Japan Aerospace Exploration Agency, Japan); (Japan Aerospace Exploration Agency, Japan); (Japan Aerospace Exploration Agency, Japan); (Japan Aerospace Exploration Agency, Japan); (Japan Aerospace Exploration Agency, Japan); (RIKEN, Japan); (RIKEN, Japan); (NICT, Japan); (NICT, Japan); (NICT, Japan)
- Laser/LIDAR remote sensing technologies can satisfy a variety of measurement and operational requirements. Specifically lasers for light detection and ranging (lidar) and its applications. These measurement techniques are finding uses in several earth science areas, including atmospheric chemistry, water vapor, aerosols and clouds, wind speed and directions, pollution, oceanic mixed layer depth, ice sheet, vegetation canopy height, biomass, surface topography, and others. Much of these sciences have been performed over the past decades using lasers, the measurements have been performed from the ground to aircraft. Improvements of knowledge in above science areas require further advances for not only higher spatial and temporal coverage by transport model (e.g. AGCM) but measured (NOT estimated) vertical profile by the space-based lidar instrument. In 2011, JAXA collaborated with NICT and RIKEN started as a new cross-sectional 3-year program to improve the developing reliable, high beam quality, efficient laser mainly in the critical 1-micron wavelengths. This laser can be used for efficient frequency conversions devices such as second and third harmonic generation and optical parametric oscillation/generation and a variety of elements common to all measurement techniques, which includes heat rejection using high thermal conductivity materials, laser diode life time and reliability, wavelength control, and suppression of contamination control. And the program has invested in several critical areas, including advanced laser transmitter technologies to enable science measurements (tree canopy, aerosol distributions, tropospheric trace gases, and wind vector), improvement of knowledge for space-based laser diode arrays, Pockels cells, advanced nonlinear wavelength conversion technology for space-based lidars. Final goal is aim to realize 15 watt class Q-switched pulse laser over 3-year lifetime.
- 14:202-2Developments of a Space-Borne Stabilized Laser for DECIGO and DPF
- (University of Electro-Communications, Japan); (University of Electro-communications, Japan); (University of Electro-communications, Japan)
- DECIGO is a space gravitational wave detector which plan to launch in 2027. DECIGO consists of three satellites that form a triangle-shape Fabry-Perot laser interferometer, and as the milestone mission, DECIGO pathfinder called DPF is also plan to launched in 2015. DECIGO and DPF require high frequency and intensity stability and also high power for their light sources, and we have developed the light source for DECIGO and DPF. An frequency-stabilized Yb:YAG laser has been developed whose frequency was locked to the saturated absorption of iodine molecules at 515nm, and the frequency stability and intensity noise of the laser were successfully stabilized to the required level for DECIGO, and DPF. The first bread-board model of the light source for DPF was developed which was reported at ICSOS2012. In order to improve mechanical stability and its compactness, the bread-board model of the light source for DPF has been revised, which consists of a semi-fiber-based light source, and a semi-rigid saturation-absorption signal detection system. The auto frequency-locking system was installed which is based on a one-chip micro computer.
- 14:402-3Compact Semiconductor Laser Modules Designed for Precision Quantum Optical Experiments in Space
- (Ferdinand-Braun-Institut, Germany); (Humboldt Universität zu Berlin, Germany); (University of Bergen, Norway); (Ferdinand Braun Institut Leibniz Institut für Hoechstfrequenztechnik, Germany); (Ferdinand-Braun-Institut, Germany); (Ferdinand-Braun-Institut, Germany); (Ferdinand Braun Institut für Höchstfrequenztechnik, Germany); (Ferdinand-Braun-Institut, Germany); (Ferdinand-Braun-Institut für Höchstfrequenztechnik, Germany); (Humboldt-Universitaet zu Berlin, Germany); (Ferdinand-Braun-Institut für Höchstfrequenztechnik, Germany)
- For most applications involving cold atom based quantum sensors such as atom interferometers or optical clocks, a deployment in outer space is highly desirable or even necessary in order to meet the stringent requirements on stability and precision. However, until now one of the main technological limitations lies in the lack of a space qualifiable technology for the lasers that are fundamental to such devices. At the FBH, we are developing a platform based on GaAs diode lasers that closes this technology gap. We report on the development of very robust, energy efficient, micro-integrated Master-Oscillator-Power-Amplifier (MOPA) and Extended Cavity Diode Laser (ECDL) modules for the deployment of cold atom based quantum sensors in space. They fit on micro optical benches not larger than 80 x 25 mm² and make use of either already space qualified or space qualifiable components and integration technologies. With MOPAs and ECDLs designed for Rubidium BEC and atom interferometry experiments at 780 nm we achieved an intrinsic linewidth of 190 kHz at 1 W and of 300 Hz at 35 mW, respectively. The MOPA module has been successfully vibration tested up to 8 gRMS random noise, and micro-integrated modules for 1060 nm that are based on the same integration technology have successfully passed vibration tests up to 29 gRMS and 1500 g pyro-shock. Further, we outline the next steps in diode laser system micro-integration that combine the MOPA and ECDL concepts with micro-integrated fibre-coupling in a hermetic housing that allows for space deployment. The technology can be transferred to other wavelengths, which opens up the prospect of space borne lasers for future applications such as inter-stellar navigation and relativistic geodesy.
- 15:002-4A High-brightness Source of Polarization-entangled Photons for Applications in Free-space
- (ICFO - Institut de Ciències Fotòniques, Spain); (Qutools GmbH, Germany); (ICFO - Institut de Ciències Fotòniques, Spain); (Qutools GmbH, Spain); (ESA, The Netherlands); (ESA, The Netherlands); (University of Waterloo, Canada); (Austrian Academy of Sciences, Austria); (University of Bristol, United Kingdom); (ICFO - Institut de Ciencies Fotoniques, Spain); (ICFO - Institut de Ciències Fotòniques, Spain); (Ludwig-Maximilians-Universität München, Germany); (ICFO and ICREA, Spain)
- Recent developments in free-space quantum communications have shown that entangled photons are not merely a tool aimed at answering fundamental questions about nature, but may well find other real world applications in the near future, such as quantum enhanced metrology or secure global quantum key distribution. One of the pre-requisites for the success of next generation field trials is the development of highly efficient, robust and space-qualified entangled photon pair sources.
Here we present a high-brightness and high-visibility source of polarization entangled photons, fulfilling the added constraints of robustness and compactness; the hardware and driving electronics was fitted on a compact breadboard for its use in out-of-the lab experiments. We achieved high flux and high visibility polarization entanglement by overlapping the spontaneous parametric down-conversion (SPDC) emission from two periodically poled potassium titanyl phosphate (PPKTP) crystals, pumped in a collinear configuration with a compact 405 nm laser diode. The spectral SPDC characteristics were chosen to maximize the detectable flux rate over long-distance atmospheric links, whereby a trade-off between available pump sources, detector efficiency and link attenuation was made. For emission at the non-degenerate wavelengths of 780 nm and 840 nm, we achieved a detected spectral brightness of 280 kcps/mW/nm, corresponding to a record total number of 640 kcps/mW over a 2.3 nm bandwidth. Importantly for quantum applications, the fidelity measured reached a staggering value of 0.98.
We present our experimental data and evaluate the source under emulated experimental conditions such as varied link attenuation and detector timing resolution. We believe that our entangled photon source will provide a valuable tool for future field trials over long-distance atmospheric free-space links.
- Optical Ground Station Technologies
- Chair:Morio Toyoshima (National Institute of Information and Communications Technology, Japan)
- 15:503-1Design of the ESA Optical Ground Station for Participation in LLCD
- (European Space Agency, The Netherlands); (ESA, The Netherlands); (European Space Agency, Germany); (European Space Agency & ESOC, Germany)
- The paper will present the optical design modifications and implementations required in ESA's optical ground station (OGS) to participate in a Laser Link Communication Demonstration (LLCD) with NASA's Lunar Atmospheric and Dust Environmental Explorer (LADEE) spacecraft. During the past years an external transmit system had been installed in the OGS (attached to the main telescope) to perform laser communication experiments with the TerraSAR-X and NFIRE satellites in LEO and operating at a wavelength of 1064nm. This system was found to be easily adaptable to operate at wavelengths around 1560nm and if duplicated (to reduce scintillation) and provided with sufficient laser power to operate up to lunar distances. Due to the separation of the transmitter and receiver system a sophisticated alignment system has been devised, which will be presented. Both the transmitter and the receiver designs are optimised for maximum throughput and will be explained, the expected link margins will be presented.
- 16:103-2Laser Ground System for Communication Experiments with ARTEMIS
- (Main Astronomical Observatory of National Academy of Sciences, Ukraine); (Main Astronomical Observatory of National Academy of Sciences, Ukraine); (Main Astronomical Observatory of National Academy of Sciences, Ukraine); (ESA, The Netherlands); (Redu Space Services S.A., ESA, Redu Station, Belgium); (National Technical University "KPI", Ukraine)
- The ARTEMIS satellite with the OPALE laser communication terminal onboard was launched on 12 July, 2001. 1789 laser communications sessions were performed between ARTEMIS and SPOT-4 (PASTEL) from 01 April 2003 to 09 January 2008 with total duration of 378 hours. Regular laser communication experiments between ESA's Optical Ground Station (OGS - altitude 2400 m above see level) and ARTEMIS in various atmosphere conditions were also performed. The Japanese Space Agency (JAXA) launched the KIRARI (OICETS) satellite with laser communication terminal called LUCE. Laser communication links between KIRARI and ARTEMIS were successfully realized and international laser communications experiments from the KIRARI satellite were also successfully performed with optical ground stations located in the USA (JPL), Spain (ESA OGS), Germany (DLR), and Japan (NICT). The German Space Agency (DLR) performed laser communication links between two LEO satellites (TerraSAR-X and NFIRE), demonstrating data transfer rates of 5.6Gbit/s and performed laser communication experiments between the satellites and the ESA optical ground station. To reduce the influence of weather conditions on laser communication between satellites and ground stations, a network of optical stations situated in different atmosphere regions needs to be created. In 2002, the Main Astronomical Observatory (MAO) started the development of its own laser communication system to be placed into the Cassegrain focus of its 0.7m AZT-2 telescope (Fe = 10.5m), located in Kyev 190 meters above sea level. The work was supported by the National Space Agency of Ukraine and by ESA ARTEMIS has an orbital position of 21.4° E and an orbital inclination of more than 9.75°. As a result we developed a precise tracking system for AZT-2 telescope (weighing more than 2 tons) using micro-step motors. Software was developed for computer control of the telescope to track the satellite's orbit and a tracking accuracy of 0.6 arcsec was achieved. A compact terminal for Laser Atmosphere and Communication Experiments with Satellite (LACES) has been produced. The LACES terminal includes: A CMOS camera of the pointing subsystem, a CCD camera of the tracking subsystem, an avalanche photodiode receiver module with thermoelectric cooling, a laser transmitter module with thermoelectric temperature control, a tip/tilt atmospheric turbulence compensation subsystem with movable mirrors, a four-quadrant photo-detector, a bit error rate tester module and other optical and electronic components. The principal subsystems and optical elements are mounted on a platform (weight < 20kg), which is located in the Cassegrain focus of the telescope. All systems were tested with ARTEMIS. The telemetry and dump buffer information from OPALE received by the control center in Redu (Belgium) was analyzed. During the beacon scan, the acquisition phase of laser link between OPALE laser terminal of ARTEMIS and LACES laser terminal started and laser signals from AZT-2 were detected by acquisition and tracking CCD sensors of OPALE. Some of the tests were performed in cloudy conditions. A description of our laser ground system and the experimental results will be presented in the report.
- 16:303-3Development of the Optical Communications Telescope Laboratory: A Laser Communications Relay Demonstration Ground Station
- (JPL, USA); (JPL, USA); (NASA Jet Propulsion Laboratory, USA); (NASA Jet Propulsion Laboratory, USA); (NASA Jet Propulsion Laboratory, USA); (NASA Jet Propulsion Laboratory, USA)
- The Laser Communications Relay Demonstration (LCRD) project will demonstrate high bandwidth space to ground bi-directional optical communications links between a geosynchronous satellite and two LCRD optical ground stations located in the southwestern United States. The project plans to operate for two years with a possible extension to five. Objectives of the demonstration include the development of operational strategies to prototype optical link and relay services for the next generation tracking and data relay satellites. Key technologies to be demonstrated include adaptive optics to correct for clear air turbulence-induced wave front aberrations on the downlink, and advanced networking concepts for assured and automated data delivery. Expanded link availability will be demonstrated by supporting operations at small sun-Earth-probe angles. Planned optical modulation formats support future concepts of near-Earth satellite user services to a maximum of 1.244 Gb/s differential phase shift keying modulation and pulse position modulations formats for deep space links at data rates up to 311 Mb/s. Atmospheric monitoring instruments that will characterize the optical channel during the link include a sun photometer to measure atmospheric transmittance, a solar scintillometer, and a cloud camera to measure the line of sight cloud cover. This paper describes the planned development of the JPL optical ground station GS-1.
- 16:503-4The Mitigation of Atmospheric Impacts on Free Space Optical Communications
- (Northrop Grumman Corporation, USA); (Northrop Grumman Corporation, USA)
- Atmospherics, in particular clouds, are key driver in the performance of free space optical communication (FSOC) systems. Clouds are composed of liquid water and/or ice crystals and depending on the physical thickness can produce atmospheric fades easily exceeding 10 dB. In these more common cases, impacts on FSOC systems may be severe. On the other hand, there are times when cloud fades may be as low as 1 or 2 dB as a result of thin, ice crystal based cirrus clouds. In these cases, the impacts on FSOC communication collectors may be limited. The ability to characterize the distribution and frequency of clouds are critical in order to understand and predict atmospheric impacts. A cloud detection system has been developed and applied to produce high resolution climatologies in order to investigate these impacts. The cloud detection system uses geostationary, multi-spectral satellite imagery at horizontal resolutions up to one kilometer and temporal resolutions up to fifteen minutes. Multi-spectral imagery from the visible wavelengths through the longwave infrared is used to produce individual cloud tests which are combined to produce a composite cloud analysis. The result represents a high spatial and temporal resolution climatology that can be used to derive accurate Cloud Free Line of Sight (CFLOS) statistics in order to quantify atmospheric effects on optical communication systems. The Lasercom Network Optimization Tool (LNOT) is used along with a mission CONOPS and the cloud database to find configuration of geographically diverse ground sites which provide a high availability system. Mission CONOPS such as a LEO to earth FSOC system and GEO to earth system will be discussed.
- 17:103-5Field Conjugation Adaptive Arrays for Reliable Satellite Downlink Coherent Laser Communications
- (Technical University of Catalonia, BarcelonaTech, Spain); (Stanford University, USA)
- Coherent optical communication through atmospheric turbulence is difficult because turbulence disrupts phase coherence. In a coherent receiver, the phase-distorted beam is combined with a perfect local oscillator beam, which can yield poor detection efficiency. Fortunately, techniques exist that can significantly improve coherent system performance in the presence of turbulence. One class of techniques employs a large monolithic aperture with adaptive optics to compensate phase fluctuations prior to detection. Another class involves spatial diversity, employing a collection of small apertures, whose detected signals are combined.
In this study, we analyze the performance of adaptive field conjugation array receivers in satellite downlink coherent laser communications. We consider coherent fiber arrays consisting of multiple subapertures, with each subaperture interfaced to a single-mode fiber. A coherent fiber array offers an advantage in terms of coupling efficiency, as the number of turbulence speckles over each subaperture is much smaller than it would be over a single large aperture. Hence, each receiver aperture can be smaller than the scale on which the signal wavefront varies, and the local oscillator phase can be matched to the signal to achieve efficient coherent downconversion.
In a field conjugation fiber array, the single-mode fiber outputs are detected, and the photocurrents are adaptively co-phased and scaled, and then summed to mitigate signal fading associated with atmospheric turbulence and compensate for imperfect fiber coupling efficiency. We quantify how field conjugation processing improves performance in the presence of turbulence, as compared to a monolithic-aperture coherent receiver having an equal total cross-sectional area. In general, the performance of such a field conjugation adaptive should improve with an increasing number of subapertures and, given a fixed collecting area, the fiber array system can offer superior performance. We quantify the performance improvement offered by array receivers in coherent optical downlinks for high-data-rate satellite communications.
- Poster Session
- Flight Demonstrations II
- Chair:Hamid Hemmati (Jet propulsion Laboratory (JPL) & California Institute of Technology, USA)
- 08:404-1[Invited] Lasercomm Activities at the German Aerospace Center's Institute of Communications and Navigation
- (German Aerospace Center, Germany)
- The German Aerospace Center (DLR) has a heritage of more than 25 years in working on optical inter-satellite and satellite-to-ground links. The Institute of Communications and Navigation (IKN) as research organization of DLR developed coherent homodyne BPSK transmission schemes with world record sensitivity as they are now implemented in the space-proven Laser Communication Terminals (LCT) for the European Data Relais System (EDRS). Further research paths followed at IKN include transmission systems optimized for atmospheric scenarios like LEO-downlinks, aircraft-downlinks, and inter-HAP links (High Altitude Platforms). For such scenarios with extreme index-of-refraction turbulence, robust adaptive optics technologies have been investigated and suitable data transceivers have been tested. Furthermore, several verification campaigns with prototype flight terminals and optical ground stations (fixed and transportable) have been performed in the last years, providing a large data basis for optimizing the long-range FSO technology. This talk shall give an overview of recent developments and ongoing scientific investigations at DLR-IKN.
09:054-2Space-QUEST: Quantum Communication Using Satellites
- (Austrian Academy of Sciences, Austria); (Austrian Academy of Sciences, Austria)
- Quantum entanglement is an intriguing feature of quantum physics and inspires fundamental questions about the principles of nature. Quantum mechanics predicts that entangled systems have much stronger correlations as is explicable with classical physics and that these correlations are independent of the distance between the particles. It is an open issue whether quantum laws, originally established to describe nature at the microscopic level of atoms, are also valid in the macroscopic domain such as long distances. The European Space Agency (ESA) has supported a range of studies in the field of quantum physics and quantum information science in space and a mission proposal Space-QUEST (Quantum Entanglement for Space Experiments) was submitted. We propose to perform space-to-ground quantum communication tests from the International Space Station (ISS). We present the proposed experiments in space as well as the design of a space based quantum communication payload.
09:254-3Performance of a Multimode Photon-Counting Optical Receiver for the NASA Lunar Laser Communications Demonstration
- (MIT Lincoln Laboratory, USA); (MIT Lincoln Laboratory, USA); (MIT Lincoln Laboratory, USA); (MIT Lincoln Laboratory, USA); (MIT Lincoln Laboratory, USA); (MIT Lincoln Laboratory, USA); (MIT Lincoln Laboratory, USA); (MIT Lincoln Laboratory, USA); (MIT Lincoln Laboratory, USA); (MIT Lincoln Laboratory, USA)
- In this talk, we describe recent measurements of the optical detector subsystem of the ground receiver to be deployed for the NASA Lunar Lasercom Demonstration (LLCD). The primary mission objective is to demonstrate a two-way selectable data rate communications link between a ground station and an optical terminal on a lunar orbiting spacecraft commissioned for the Lunar Atmosphere and Dust Environment Explorer (LADEE). A secondary goal is to demonstrate two-way time of flight measurements between the terminals with sub-cm resolution using the optical data communications channel. The focus of this talk will be on the optical performance of the downlink between the spacecraft (transmitting a ~ 0.5 W average power beam near 1550 nm from a 10-cm aperture with 16-ary pulse position modulated data stream) and the optical receiver on the ground terminal. Laboratory tests of the optical receiver performance with an incident PPM signal with ~5-GHz time slots and ½-rate serially-concatenated PPM forward error-correction coding showed error-free performance at 38-622 Mb/s with a receiver sensitivity of 1-2 incident photons/bit.
09:454-4From SILEX/LOLA to High Data Rate Optical Telemetry for LEO Satellite
- (EADS Astrium, France); (EADS Astrium, France); (EADS Astrium, France)
- The continuous improvement of performances of Earth Observation satellites results in dramatic increase of image volume, asking for Payload Telemetry with higher downlink capability. Thanks to the intrinsic high operating frequency (hundreds of THz) leading to very high optical antenna gain, free-space optical communications offer the technology breakthrough required by future Earth Exploration Satellites for their High Rate Payload Telemetry. LOLA programme has demonstrated the maturity of this technology with an atmospheric propagation channel (robustness to fading). However, as communication performances require clear sky propagation conditions, it is necessary to implement optical ground stations on favourable sites to reach operational system availability. This paper presents the architecture and performances of LEO-to-ground optical telemetry system operating at 1.55 µm laser wavelength, as investigated in the frame of the study conducted for CNES. The choice of 1.55 µm technology is justified by the analysis of eye safety constraints, but also by the growth capability offered by wavelength multiplexing (several laser wavelengths in the same optical beam). The optical link sizing is derived from the link budget consolidated on the basis of SILEX & LOLA flight results. The maturity level of the key technologies required for the space segment are analysed in order to derive technology pre-developments required prior to an operational system.
- Flight Demonstrations III
- Chair:Naoto Kadowaki (National Institute of Information and Communications Technology, Japan)
- 10:305-1[Invited] Status of the European Data Relay Satellite System
- (ESA, The Netherlands); (ESA, The Netherlands); (ESA, The Netherlands); (ESA, The Netherlands); (ESA, The Netherlands); (ESA, The Netherlands); (ESA, The Netherlands); (ESA, The Netherlands); (ESA, The Netherlands); (ESA, The Netherlands); (ESA, The Netherlands); (ESA, The Netherlands); (DLR, Germany); (DLR, Germany); (DLR, Germany); (DLR, Germany); (Astrium, Germany); (Astrium, Germany); (Astrium, Germany); (Astrium, Germany); (Astrium, Germany); (Astrium, Germany); (Astrium, Germany); (Astrium, Germany); (Astrium, Germany); (Astrium, Germany); (Tesat Spacecom, Germany); (Tesat Spacecom, Germany); (Tesat Spacecom, Germany); (Tesat Spacecom, Germany); (Tesat-Spacecom, Germany); (OHB, Germany); (OHB, Germany); (OHB, Germany); (OHB, Germany)
- The European Data Relay Satellite System (EDRS) is under implementation within the Advanced Research in Telecommunications Systems Programme (ARTES-7) of the European Space Agency (ESA). After a successful demonstration of the Semiconductor-laser Inter-satellite Link EXperiment (SILEX) in 2001 between Artemis GEO satellite and SPOT-4 LEO satellite, the EDRS will become the first European data relay system providing a wide range of operational services (both optical and Ka-band based). A major difference between SILEX and EDRS is the selected optical technology and targeted performances of the laser links between the LEO satellite users and the GEO satellite nodes. The EDRS optical inter-satellite links (OISLs) are based on optical Laser Communications Terminals (LCT) which are developed and qualified by TESAT Spacecom under DLR German national funding . These LCTs are featuring a significantly increased data transmission rate, compared to SILEX technology, and at the same time reduced mass and size. The joint European Commission / ESA Global Monitoring for Environment and Security (GMES) programme will be the first customer of the EDRS service (Sentinel 1A/B and 2A/B LEO satellites). This paper will provide an overview of the EDRS project and the current development status of its LCTs.
- 10:555-2[Invited] 10-Gb/s Lasercom Terminal for Satellites
- (Jet propulsion Laboratory (JPL) & California Institute of Technology, USA); (Jet Propulsion Laboratory (JPL), USA)
- Progress in developing a highly compact lasercom flight terminal, with 5-cm transmit and receive aperture, will be reported. This terminal has the capability to downlink at the data-rate of 10 Gb/s from 1000 km range (low-earth-orbit) to a 60-cm ground aperture. It has the capacity for extendibility to higher data-rates and longer communications ranges at higher orbits. The flight subsystem consists of an optical head with common path for both data transmission and beacon signal reception. This assembly consists of a quadrant detector for acquisition and tracking, and a fast steering mirror to compensate for platform jitter. The entire optics assembly is situated on a two-axis coarse pointing gimbal has low jitter, and is capable of providing 10-urad pointing resolution. The fine-steering mirror, together with the coarse pointing gimbal, result in <5urad beam pointing to the ground station. This pointing resolution is well below the 50 urad beam-width of the transmit laser. To suppress the background light entering the quad detector, the earth-emanated laser is modulated at 20 kHz. The 2-W fiber-amplified laser, the processor assembly, controllers, drivers, and power converters are located in a separate assembly. The laser signal is fed into the opto-mechanical assembly via a fiber. The transmitter uses four channels in the C-band. Each of the four 0.5-W lasers can be modulated at rates up to 2.5 Gb/s data. Flight grade components are used for all electro-optical and electronics parts. Results of field-testing, including links form airplane to ground are described.
The work described here was carried at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration
- 11:205-3[Invited] Studies on Candidate Approaches for Satellite-Ground Laser Communications
- (National Institute of Information and Communications Technology, Japan); (National Institute of Information and Communications Technology, Japan); (National Institute of Information and Communications Technology (NICT), Japan); (National Institute of Information and Communications Technology, Japan); (National Institute of Information and Communications Technology, Japan)
- A satellite-ground laser communication system contains various functions such as tracking, coupling, coding, and so on. Besides, to increase the availability of the satellite-ground links, the location of the ground station is one of the factors to be considered. Currently aiming at the progress of the satellite-ground laser communications, we study candidate approaches to provide those functions. In this work, we will show the current status of our activities concerning the small optical transponder to be mounted on a satellite, the site selection for optical ground stations, elemental technologies for tracking and coupling of light. In addition, the satellite laser ranging system is introduced that shares the telescope of the optical ground station with the system for the satellite-ground laser communications.
- 11:455-4[Invited] Optical Wireless Communications and Potential Applications in Space
- (Oxford University, United Kingdom)
- Optical wireless has made good progress recently, with rates of 100s of Mbit/s demonstrated using visible light communications and Gbit/s optical wireless systems operating in the infrared region of the spectrum. Space is a potentially attractive environment for optical wireless, due to the line of sight channels that are available between objects in space, and the requirements for low mass systems of the type that optical wireless can potentially produce. In this presentation we review some of the recent progress in this area, including details of systems implemented at the University of Oxford, with an emphasis on how they might be used in a space environment.
- Optical System Designs I
- Chair:Dirk Giggenbach (German Aerospace Center, Germany)
- 14:006-1Design of Engineering Model of Corner Cube Retro-reflector by Evaluating Far Field Diffraction Pattern
- (National Institute of Information and Communications Technology, Japan); (Hitotsubashi University, Japan); (Jisedaitech, L. P., Japan); (Universe Ltd., Japan); (Optogreen Co., Ltd., Japan)
- We have designed and tested a corner cube retroreflector (CCR) for laser ranging in order to work in maximum efficiency in space. In this report we studied simulation and measurement of far filed diffraction pattern (FFDP) of various types of engineering model of CCRs in material, dihedral angle, coating on back surface. The experimental optics are setup to view and record polarizing components of FFDP, conducting a scale calibration. The agreement has been confirmed on FFDP between measurement and simulation. Also, we have developed a simplified thermal model which explain behavior of optical response of CCR and report a significant effect on FFDP due to thermal input to test setup. Design of CCR in a flight model will be discussed.
- 14:206-2Control Algorithm for Adaptive Optics in Remote Sensing Telescope
- (University of Tokyo, Japan)
- We are developing an adaptive optics system for earth observing remote sensing telescopes. The vibration during the launch and thermal deformation in the orbit degrade the optical performance. We use the deformable mirror to compensate the distorted wavefront that derived from these degradation factors. The wavefront aberration is estimated by image-based approach not only for simplified architecture but also for the robustness against observed scene. In remote sensing, it is difficult to use a reference point source unless the satellite controls its attitude toward a star. We propose the control algorithm of the deformable mirror on the basis of the extended scene instead of the point source.
- 14:406-3Progress on Non-Linear SFG Use for High Resolution Imaging
- (Xlim, France); (Xlim, France); (Xlim, France); (Xlim, France); (Xlim, France); (Horiba Scientific, France); (Universitaet Paderborn, Germany); (Universitaet Paderborn, Germany)
- Frequency conversion are commonly used in the field of radio and microwave applications for a long time. In the optical domain, this operation can be achieved thanks to various nonlinear parametric interactions such as second harmonic, difference frequency and sum frequency generation (SFG) in a nonlinear crystal or waveguide. In particular, SFG in a periodically poled Lithium Niobate (PPLN) waveguides allows a very efficient conversion of an infrared wave into a visible one by using a pump source as demonstrated in many applications.
In the field of high resolution imaging in astronomy, SFG process could allow to detect a weak infrared signal in the visible domain, where detectors such as silicon avalanche photodiodes are very efficient. As an extension of this work, we have recently demonstrated our ability to analyze the coherence properties of an infrared signal through an up-conversion process in a two and a three-arm interferometer (Ceus ICSO 2010).
In this previous work, we were limited by the intrinsic spectral acceptance of the PPLN waveguides: if a large spectral bandwidth infrared source is converted through a SFG process with a single line pump, the PPLN spectral acceptance restricts the nonlinear effect to a narrow spectral bandwidth of the source.
To overcome this spectral limitation, we intend to use the SFG process over an enlarged spectral domain by using a frequency comb pump source.
We report here the first step of this work, consisting in the experimental implementation of a SFG process powered by a pump spectral doublet. By analyzing the converted signal, we numerically and experimentally demonstrate a frequency spectral compression, driving to a coherence length increase, between the infrared input signal and the visible one converted through the SFG process. The experimental setup, based on an up-conversion interferometer, demonstrates an experimental frequency spectral compression factor of 3.56.
- 15:006-4Space Laser Communication Network
- (Changchun University of Science and Technology, P.R. China); (Changchun University of Science and Technology, P.R. China); (Changchun University of Science and Technology, P.R. China); (Changchun University of Science and Technology, P.R. China); (Changchun University of Science and Technology, P.R. China)
- With the number of satellite cluster, space station and planet detector is sharply increasing, the next challenge we face is to set up space laser communication network.However, it is not only difficult but also cumbersome to use point-to-point laser communication terminal as a data node terminal antenna. The characteristics of rotational paraboloid is that light beam incident from any direction to the parabolic focus will refract on surface of parabolic,the beam propagation direction is parallel to the symmetry axis of paraboloid ,this structure of optical antenna to overcome constraint of ATP subsystem,when multiple platforms communicate with each other at same time. In this paper we designed an antenna which can meet demand that at least two terminals communicate to it , and next work is we make rotational paraboloid improvement according to space platform orientation.
- Fiber Optic Component Qualification (ICSOS/ICSO Joint Session)
- Chair: Barbero Juan (Alter Technology, Spain)
The papers of Session 7 are available in ICSO 2012 Proceedings.
- 15:507-1Radiation-Hardened Nano-Particles-Based Erbium-Doped Fiber for Space Environment
- (Institut Electronique du Sud, France); (Institut Electronique du Sud, France); (Prysmian Group/Draka Comteq, France); (Prysmian Group/Draka Comteq, France); (Prysmian Group/Draka Comteq, France); (Prysmian Group/Draka Comteq, France); (CNES, France); (Thalès Alenia Space, France); (Institut Electronique du Sud, France)
- 16:107-2Radiation Hardening of Rare-Earth Doped Fiber Amplifiers
- (Laboratoire Hubert Curien UMR CNRS 5516, France); (CEA, DAM, DIF, France); (CEA, DAM, DIF, France); (iXFiber, France); (iXFiber, France); (iXFiber, France); (iXFiber, France); (Laboratoire Hubert Curien UMR CNRS 5516, France); (Laboratoire Hubert Curien UMR CNRS 5516, France); (Università degli Studi di Palermo, Italy)
- 16:307-3Radhard Optical Patchcords for Satellites Using Liquid Crystal Polymer Jacket
- (Linden Photonics, Inc., USA); (Linden Photonics, Inc., USA)
- 16:507-4New Optical Fiber for Short Distance Network and Elevated Temperature Environment
- (Corning Inc., USA)
- 17:107-5ESCC Standards, Evaluation and Qualification of Optical Fiber Connector for Space Application
- (DIAMOND SA, Switzerland)
- Poster Session / Tutorials
- Optical System Designs II
- Chair:Josep Maria Perdigues Armengol (ESA, The Netherlands)
- 08:308-1High Precision Encoders for GEO Space Applications
- (Tesat Spacecom, Germany); (Tesat Spacecom, Germany); (Tesat Spacecom, Germany); (Tesat Spacecom, Germany); (Tesat Spacecom, Germany); (Tesat Spacecom, Germany); (Tesat Spacecom, Germany); (Renishaw, United Kingdom); (Renishaw, United Kingdom); (Renishaw, United Kingdom); (Renishaw, United Kingdom); (DLR, Germany)
- High precision encoders are used by earth observation instruments and in mechanisms for Laser Communication Terminals. Tesat Spacecom has developed and tested a micro-radian resolution encoder for the Laser Communication Terminal - LCT, designed for precision pointing applications especially in GEO environments with 15 years lifetime and in high duty cycle applications. The encoders will be used for the LCTs on the Sentinel 1A and EDRS LCTs. The design principles and performance parameters will be presented.
- 08:508-2BRDF Prediction Using Surface Micro-Roughness Measurements
- (EADS - ASTRIUM & ESA, Germany); (ESA, The Netherlands)
- Straylight assessment and minimization are standard tasks in the design of high performance optical instruments. An important variable in this regard is the scattering profile of the instrument's optical surfaces. In the case of reflective samples, this is commonly specified through the Bidirectional Reflectance Distribution Function (BRDF). In spite of its widespread use, BRDF experimental measurements are challenging and time consuming. Thus, alternatives that allow for accurate approximations of the BRDF are attractive.
This work explores the Rayleigh-Rice vector perturbation theory (RR) as a means to accurately and efficiently determine the BRDF of an optical reflective sample. Specifically, aerial topography interferometric measurements are used to compute the BRDF. The predicted scattering profiles are consequently compared to experimental BRDF measurements. Based on these results, it is concluded that the RR method is a promising technique to specify the scattering characteristics of an optical sample within orders of magnitude.
- 09:108-3High-Precision Narrow-Band Optical Filters for Global Observation
- (Showa Optronics Co., Ltd., Japan); (Showa Optronics Co., Ltd., Japan); (Showa Optronics Co., Ltd., Japan); (Showa Optronics Co., Ltd., Japan); (Japan Aerospace Exploration Agency, Japan); (Japan Aerospace Exploration Agency, Japan); (NEC TOSHIBA Space Systems, Ltd., Japan); (NEC TOSHIBA Space Systems, Ltd., Japan); (NEC TOSHIBA Space Systems, Ltd., Japan)
- The earth observation satellites are launched to monitor global and long-term climate change and water circulation, and so on. These observations will also help us to increase prediction accuracy of future environmental changes. The satellites should obtain global observation frequently by an efficient way because the environmental condition of the earth makes changes day by day. The Second-generation Global Imager (SGLI) on the Global Change Observation Mission (GCOM) is multi-band optical imaging radiometer. It will provide high accurate measurements of Ocean, Atmosphere, Land and Cryosphere with about 2 days frequency. To obtain accurate multi spectral data of wide swath width, SGLI needs narrow band pass filters with high precision and long length. The optical band pass filters used for such imager require high uniformity of center wavelength. Especially, when the pass band width becomes narrower than 10nm or so, the variation of center wavelength across the length of a filter causes a significant measurement error. However, the uniformity of most of the conventional filters coated by vacuum evaporation has a few tenths of a percent over the length of 100mm because of the fluctuations of vapor distribution in a coating process. In this paper, the relation between the geometry of substrate fixture and film thickness variation on substrate is discussed. Actually we demonstrate experimentally that the center wavelength uniformity of the band pass filters is easily improved better than 0.1%PP over the length of 100mm. In addition, it is shown that the center wavelength shift due to the telecentricity, or inclination angle of the chief ray in image space, can be compensated for by controlling the distribution of center wavelength on filter substrate.
- 09:308-4Wide-Field-of-Regard Pointing, Acquisition and Tracking-System for Small Laser Communication Terminals
- (German Aerospace Center (DLR), Germany); (German Aerospace Centre, Germany)
- Wide-Field-of-Regard Pointing, Acquisition and Tracking-System for small Laser Communication Terminals
Pointing, Acquisition and Tracking (PAT)-systems are one of the central parts of a Laser Communication Terminal. In Laser Communication Terminals a staggered PAT-system consisting of Coarse Pointing Assembly (CPA) and Fine Pointing Assembly (FPA) is common. The CPA provides a Wide-Field-of-Regard (FoR) and the FPA a precise and fast alignment of the beam to the communication partner. The disadvantage is the mechanical complexity. This paper presents the development challenges of a Wide-Field-of-Regard PAT-system for small Laser Communication Terminals by combining and miniaturizing the functionality of the CPA and FPA to a single actuator.
To get a small and lightweight Wide-Field-of-Regard PAT-system, the number of moving parts has to be minimized. Therefore, the system consists of an optical setup that provides a large FOV and one single mirror actuator for beam steering - thus, CPA and FPA can be combined in just one moving component. The actuator is controlled by a Digital Signal Processor (DSP) The tracking sensor is a 4-Quadrants-Detector (4QD). During the acquisition mode, the actuator moves in a predefined scan pattern until a signal can be detected on the 4QD. Consequently the system changes to tracking mode.
Our design approach succeeded in a Field-of-Regard (FoR) of up to 45° without traditional CPA. The scan time for the complete FoR is less than 1 second. The block diagram and measurements taken with the prototype in the laboratory will be presented in this paper.
- 09:508-5Wide Angle Cross-Folded Telescope for Multiple Feeder Links
- (RUAG Space, Switzerland); (RUAG Space, RUAG Schweiz AG, Switzerland)
- An optical design for a reflective wide angle afocal telescope is presented. The telescope is a transmit antenna for optical downlinks from GEO. The Antenna features three separate input ports for three different feeders and images them to three different foot prints on ground. These foot prints spawn over the western Mediterranean Sea from Portugal to Greece. Thus three actually different channels are served by a single optical telescope. In order to reach the desired overall extend of the field, the ocular mirrors were split into three individual mirrors, while the front mirrors of the objective serve all three channels. The telescope is folded twice: in y-direction to obtain an off-axis configuration and in x-direction to accommodate the three channels. The specification data of the telescope are:
Entrance Pupil Diameter: 200 mm
Afocal Magnification: 8
Field of View in Y-Direction: ±0.62°
Fields of View in X-Direction: 1: 0°±0.64°
Wave Front Error: 50-100 nm
- Terrestrial and Space Technologies
- Chair:Volodymyr Kuzkov (Main Astronomical Observatory of National Academy of Sciences, Ukraine)
- 10:309-1Low Latency Data Transmission Using Wireless and Wired Communications
- (National Institute of Information and Communications Technology, Japan); (National Institute of Information and Communications Technology, Japan); (National Institute of Information and Communications Technology, Japan)
- High speed transmission is indispensable to mitigate huge data communication demands. In addition, latency is a very important figure to describe performance of transmission systems for particular applications, such as data transmission for earthquake early warning, transaction for financial or banking businesses, interactive services such as online games, etc. Latency consists of delay due to signal processing at nodes and transmitters, and of signal propagation delay due to finite speed of electromagnetic waves. Signal processing delay can be reduced by using parallel processing based on large scale integration CMOS technologies. However, propagation delay has an absolute limit because any electromagnetic waves should not be faster than light in vacuum. Thus, the lower limit of the latency in optical transmission systems using conventional single mode fibers (SMFs) depends on the speed of light in SMFs which is 33% slower than the speed of light in vacuum c. In free space wireless optic systems, signals can propagate with the speed c, so that the latency would be smaller than in optical fiber communication systems. For example, optical wireless systems using LEO satellites would transmit data faster than optical submarine cable systems, when the transmission distance is longer than a few thousand kilometers. Photonic crystal fibers (PCFs) can have very low effective refractive index, and can propagate light much faster than in SMFs. Thus, cables with PCFs also can reduce the latency in transmission. In this presentation, we will discuss the latency and capacity of wireless and wired optical communication systems. We will also describe possible applications of ultra low latency transmission.
- 10:509-2Integrated Optical Modulator for Adaptive Digital Modulation and Analogue Applications
- (National Institute of Information and Communications Technology, Japan); (National Institute of Information and Communications Technology, Japan); (National Institution of Information and Communications Technology, Japan); (National Institute of Information and Communications Technology, Japan)
- High-speed adaptive modulation technique is highly demanded for space optical communication systems for realization of reliable connectivity. For the adaptive modulation, however, electrical method using an IQ modulator limits the transmission speed because of a bandwidth of the electrical components such as a digital-to-analogue converter. Integrated lithium niobate (LN) optical modulator is a promising candidate for recent high-speed optical networks due to its robustness and high linearity based on matured technology, and thus, has been drastically developed for reduction of footprint of an optical transmitter. A dual-polarization quadrature phase-shift keying (DP-QPSK) modulator, which consists of two optical IQ modulators in parallel with the polarization orthogonally and a polarization beam combiner, has been matured for 100GbE with 28-Gbaud DP-QPSK coherent systems. We reported 16-ary quadrature amplitude modulation (QAM) with a coherent polarization synthesis technique using the DP-QPSK modulator. When the polarizer set at the optical output of the modulator worked as an intensity trimmer, two QPSK signals are multiplexed to generate square 16-QAM signal. Moreover, a resultant symbol rate will be greater than 30 Gbaud, for example, 30-Gbaud 16-QAM provides 120 Gb/s, because this method is based on the optical synthesis technique with four electrical binary signals launched into the modulator. This structure and technique, which is so-called "optical digital-to-analogue converter," will be useful for high-speed adaptive optical modulation with binary PSK, QPSK and 16-QAM, whose resultant spectral efficiencies are 1, 2 and 4 b/s/Hz, respectively. On the other hand, the nested IQ modulator structure is also available for analogue applications such as millimeter-wave signal generation with high accuracy using precise control of the modulator. In this presentation, we will discuss the demonstration of binary PSK, QPSK and 16-QAM signal generation with the DP-QPSK modulator as well as a millimeter-wave signal generation.
- 11:109-3Integrated Indium Phosphide Coherent Optical Receivers and Transmitters
- (Freedom Photonics, USA); (Freedom Photonics, USA); (Freedom Photonics, USA); (Freedom Photonics, USA); (Freedom Photonics LLC, USA); (Freedom Photonics, USA)
- Freedom Photonics is developing miniature high-speed optical transmitter and receiver technology for optical communications between airborne, ground and satellite stations. Widely tunable chip-scale compact optical transmitters and receivers have been developed, with very small chip footprint achieved (0.5x3.5mm2 for transmitter, 1x2.5mm2 for receiver). Both the transmitter and receiver chips are being fabricated on the same wafer using the same fabrication steps, and can be produced as a single, monolithic chip. This technology has been realized in a radiation hard Indium Phosphide photonic integration platform. High level of integration eliminates the need for fiber coupling between different sub-elements (laser; optical amplifier; optical modulator; photodetector) which results in very low optical interconnect losses (<0.1dB), and high mechanical robustness. These coherent transmitters and receivers are designed to generate and demodulate QPSK optical modulation at clock-rates up to 25 GHz, leading to a total channel data rate of 100 Gbps for a polarization multiplexed signal. The transmitters and receivers are widely-tunable, designed to reach any of 50 wavelength channels within the optical C-band.
- 11:309-4Log-APP Detection for FSO Repetition MIMO Links
- (University of Kiel, Germany); (University of Kiel, Germany)
- Free-space optical (FSO) data links can provide high bandwidth and secure data transmission. A robust solution on the physical layer to minimize channel impacts, such as atmospheric turbulence, is to use spatial diversity (multi-aperture MIMO) in conjunction with repetition coding. In this contribution, the optimum detector in the sense of minimizing the bit error rate (BER), an a posteriori probability (APP) detector, is adopted to the FSO channel model. We derive a general metric for FSO transmission and present a metric that improves the BER performance if the noise process at the receiver side is correlated. Simulation results verify that the proposed receiver outperforms conventional soft-decision detection if the noise process is colored.
- 11:509-5Channel Estimation for FSO Channels Subject to Gamma-Gamma Turbulence
- (Universsity of Texas at Dallas, USA)
- The problem of estimating the signal intensity level in a turbulent optical channel when the channel is subject to gamma-gamma fading is investigated. Such an estimation is of paramount importance to a direct-detection, on-off-keying (OOK), free-space optical (FSO) communication receiver where the knowledge of the received signal intensity level is required to set the optimum receiver threshold. An estimator, motivated by the maximum a posterior (MAP) rule, is proposed. Furthermore, a linear minimum mean-square estimator (LMMSE) is proposed. The performances of the proposed estimators are investigated using simulation and analytical tools. Furthermore, Cramer-Rao bound for the above scenario is computed and is compared to the performances of the proposed estimators. Finally, a discussion on the complexity versus performance of the proposed algorithms is provided.
- Atmospheric Turbulence and Coding Algorithm
- Chair:Dominic O'Brien (Oxford University, United Kingdom)
- 14:0010-1Turbulence Effects on Bi-Directional Ground-to-Satellite Laser Communication Systems
- (ONERA, France); (ONERA, France); (ONERA, France); (ONERA, France); (National Institute of Information and Communications Technology, Japan); (National Institute of Information and Communications Technology (NICT), Japan); (CNES, France); (CNES, France)
- Satellite-to-ground communications are currently facing new challenges in terms of data rates. With expected data rates as high as tenth of Gbps, optical technologies should contribute to solve the issue. Unfortunately turbulence can severely jeopardize optical communication performance. So as to evaluate the impact of turbulence on data rates and on optical system design, an end-to-end code, based on phase screen techniques, has been adapted to simulate the propagation channel in LEO-Ground configurations. Compared to analytical expressions, our simulation tool allows the joint account of pointing and turbulence effects, and also allows to jointly derive spatial and temporal statistics. We illustrate the use of this tool by modelling flux fluctuations in a telescope receiver for up and down link between LEO satellite and an optical ground station. For down-link, the access to the experimental optical data recorded by NICT ground station of OICETS satellite allows to discuss the simulated results in view of the development of the future ground to space optical links.
- 14:2010-2Rateless Codes Performance Analysis in Correlated Channel Model for GEO Free Space Optics Downlinks
- (University of Palermo, Italy); (University of Palermo, Italy); (University of Palermo, Italy); (Università di Palermo, Italy); (University of Palermo, Italy); (Universita' di Palermo, Italy)
- Free Space Optics (FSO) technologies for satellite communications offer several advantages: wide bandwidth, high rate capability, immunity to electromagnetic interference and small equipment size. Thus, they are suitable for inter-satellite links, deep space communications and also for high data rate ground-to-satellite/satellite-to-ground communications. Nevertheless, FSO links suffer impairments that cause power signal degradation at the receiver. Scattering and absorption cause power signal attenuations predictable by suitable deterministic models. Optical turbulence causes random irradiance fluctuations which can generate signal fading events and can thereby only be predicted by statistical models. Attenuation and fading events can corrupt FSO links, and so it would be recommended to add mitigation error codes on the communication link. FSO channel can be described as an erasure channel: fading events can cause erasure errors. We have identified in rateless codes (RCs) a suitable solution to be employed in FSO links. RCs do not need feedback and they add a redundant coding on the source data that allows the receiver to recover the whole payload, despite erasure errors. We implemented two different of rateless codes: Luby Transform (LT) and Raptor. We analyzed their performances on a simulated turbulent GEO FSO downlink (1 Gbps - OOK modulation) at a 1,06 µm wavelength and for different values of zenith angles. Assuming a plane-wave propagation and employing Hufnagel-Valley, we modeled the downlink using: 1) a temporal correlated channel model based on Gamma-Gamma probability distribution and 2) an irradiance covariance function that we converted on a time function using Taylor frozen eddies hypothesis. Our new channel model is able to simulate irradiance fluctuations at different turbulence conditions as it will be shown in the full paper. We will also report performance results of LT and Raptor codes at overhead range varying between 0 and 50% and for different values of source packets.
- 14:4010-3A LT-Based Multi-Rate Transmission Scheme with Fast Decoding for Satellite Laser Communication
- (Nagoya Institute of Technology, Japan); (Nagoya Institute of Technology, Japan); (Nagoya Institute of Technology, Japan); (National Institute of Information and Communications Technology, Japan); (National Institute of Information and Communications Technology, Japan); (National Institute of Information and Communications Technology, Japan)
- There are expanding demands for satellite laser communications because it enables an extremely high capacity. The satellite laser communication, however, has several technical problems to be solved. One of them is air scintillation which causes a burst decreasing of receive optical power, resulting in poor transmission performance. To tackle this problem, a forward error correction (FEC) is used in general and the efficient FEC for the satellite laser communication is required. In particular, the fast decoding is important since the transmission rate is very high. In this case, it is known that the application of erasure channel is effective in which the channel condition is simplified into two states: correct and erasure. If the receive power is sufficiently high, the receive symbol is treated as "correct", otherwise "erased". Then, an erasure code in which the fast decoding is available is applied and the erased symbol is recovered. In addition, a multirate transmission is also effective in satellite communication to balance the quality and rate of transmission, e.g., the adaptation for data contents, weather at the earth station, or link distance. Therefore, we propose an LT-based multirate transmission scheme with fast decoding for satellite laser communication. The performance of the proposed scheme is evaluated through computer simulations.
- 15:0010-4Study on Error Coding Program for Implementation in SOTA
- (National Institute of Information and Communications Technology (NICT), Japan); (National Institute of Information and Communications Technology, Japan); (National Institute of Information and Communications Technology, Japan); (National Institute of Information and Communications Technology, Japan); (National Institute of Information and Communications Technology, Japan); (Nagoya Institute of Technology, Japan); (Nagoya Institute of Technology, Japan)
- Development of a Small Optical TrAnsponder(SOTA) on board a micro-satellite is conducted by the National Institute of Information and Communications Technology (NICT). The fading deteriorates communications quality. To cover this problem, SOTA is equipped with error correcting system. However, error correcting system consumes a lot of memory. It is necessary to take measures because of not enough resource in a micro-satellite. In this paper, we describe a method with error coding program for a micro-satellite.
- Small Satellites I
- Chair:Stephane Gagnon (Neptec Design Group, Canada)
- 15:50Post-1[Post Deadline Paper] Network Architectures for Space-Optical Quantum Cryptography Services
- (Tesat-Spacecom GmbH & Co. KG, Germany); (Tesat Spacecom, Germany); (Tesat Spacecom, Germany); (Austrian Institute of Technology GmbH, Austria); (AIT Austrian Institute of Technology GmbH, Austria); (Eutelsat S.A., France); (Eutelsat SA, France); (Eutelsat, France); (Eutelsat S.A., France); (Austrian Academy of Sciences, Austria); (Austrian Academy of Sciences, Austria); (ESA, The Netherlands)
- Quantum cryptography enables the distribution of 'information-theoretically' secure (ITS) keys, whose secrecy is guaranteed by the laws of quantum physics. Such a level of security is superior to conventional 'classical' cryptography whose security is at most 'computational', and even this lower security level is unverified in many cases. Fiber-based quantum key distribution (QKD) systems for link distances up to hundred kilometers are already available on the market since several years. However, there is no practical way to cover larger distances without employing a space-based relay. Therefore we propose here network architectures for space-optical quantum communication services. By a trade-off process between performance and cost, we have identified three scenarios that are capable to provide a large number of users on ground with ITS keys at affordable service fees. Here we detail the architectures of space, ground and control segment for operational space-based QKD services.
- 16:1011-1Small Photon-Entangling Quantum Systems (SPEQS) for LEO Satellites
- (National University of Singapore, Singapore); (University of Strathclyde, Singapore)
- We propose to build and launch a complete quantum optics system to test fundamental quantum physics in low earth orbit. This system (SPEQS) must contain a quantum light source, and detectors for analyzing the quantum state. A successful test will pave the way for more advanced experiments including long distance distribution of quantum entangled photons and probe any interaction between gravity and quantum physics. To be cost effective, the scientific package will be designed to fit a 1U CubeSat. The package has a maximum volume of 300 mililitres and a mass of 300 gm and must be able to operate on 1.5W of electrical power. We will present a progress report and future plans to distribute photons between satellites or from satellite-to-earth.
- 16:3011-2A Modular Solution for Routine Optical Satellite-to-Ground Communications on Small Spacecrafts
- (RUAG Space, RUAG Schweiz AG, Switzerland); (RUAG Space, RUAG Schweiz AG, Switzerland); (RUAG Space, RUAG Schweiz AG, Switzerland); (RUAG Space, RUAG Schweiz AG, Switzerland)
- Small satellite's prime contractors and operators are currently looking for innovative solutions allowing for increased data download capabilities at comparable on-board resource constraints on micro-satellites. One possible solution is to increase the data rate per downlink. In this paper, an optical downlink solution is discussed, which is targeted for small satellites around 150kg and higher. In its space segment, a modular optical communications system design enables versatility and scalability starting at minimal requirements on resources and footprint. On system level, depending on mission needs, several scalability options are available e.g. for a further increase of data volume per downlink, for higher robustness against jitter or even for downscaling if merely access to optical spectrum is beneficial for the mission's operational planning.
In 2010 RUAG Space started the development of a complete system called OPTEL-µ, including a small space terminal and a ground terminal for optical space-to-ground downlinks with support from ESA. The OPTEL µ product aims at direct-to-ground laser communications and follows the request for the elementary features smallness, robustness and versatility. The OPTEL-µ baseline product of the space segment part is targeting a 4.5 kg, 4.5 litres and 45 W space terminal that features a data rate of up to 2 Gbit/s for direct-to-ground laser communications. The emphasis lies on a compact and robust terminal that mainly addresses the needs of the emerging market of micro satellites.
This paper describes the baseline architectural concept of the OPTEL-µ system for downlinks from micro satellites by laser communications. Emphasis is given to accommodation aspects in view of modularity and scalability of the communication system, discussing options to customize the baseline OPTEL-µ system to specific needs of the platform or mission.
- 16:5011-3Implementation of Inter and Intra Tile Optical Data Communication for NanoSatellites
- (Politecnico Di Torino, Italy); (Politecnico di Torino, Italy); (Politecnico Di Torino, Italy)
- Wireless communication systems have still not been widely used in space, but they can bring several advantages to on-board communication of small satellites. First of all, it is quite simple to connect wireless modules, since no wiring is needed. Secondly it is simple to create a broadcast channel among modules. Moreover in small satellites, there is not much free space for wires and integration of many sensors and other subsystems using a wired solution alone is quite complex. This paper discusses design technique for optical wireless transceiver for modular satellites using low cost COTS components. Modularity is achieved by using architecture that uses smart tiles or panel bodies that can be connected together at different angles. The proposed transceiver structure uses Infrared Light Emitting Diode to transmit pulses in near infrared spectrum .The receiver circuit consists of Photodiode, preamplifier, post amplifier and a comparator stage. Since noise is a major problem for receiver, a very low noise preamplifier and post amplifier stages have been selected. Since the communication system is inside the satellite, there is possibility of sunlight to enter from small holes and blind the receiver. This problem is solved by attenuation circuit. .BER has been calculated by changing the distance between transmitter and receiver and results calculated. Texas Instruments MSP430 micro controller receives the digital signal for further decoding and protocol management. This optical wireless module is fully scalable depending on the needs of the system and can coexist with more traditional wired communication channels as required. The aim is to connect some sensors with the wired solutions and others using wireless solutions. Hence, we gain advantage of less physical wires inside small satellite, freedom to choose optical and wired modules and different sensors based on their bandwidth demands.
- 17:1011-4Optical Communication Experiment Using Very Small Optical TrAnsponder Component on a Small Satellite RISESAT
- (NICT, Japan); (National Institute of Information and Communications Technology, Japan); (National Institute of Information and Communications Technology (NICT), Japan); (NICT, Japan); (National Institute of Information and Communications Technology, Japan)
- We overview optical communication experiment between a Very Small Optical TrAnsponder component on a small satellite Hodoyoshi 2 callsed RISESAT and the Optical Ground station.
- Small Satellites II
- Chair:Hiroo Kunimori (National Institute of Information and Communications Technology, Japan)
- 08:3012-1ShindaiSat: A Visible Light Communication Experimental Micro-Satellite
- (Shinshu University, Japan); (Shinshu University, Japan); (Shinshu University, Japan); (Shinshu University, Japan); (Shinshu University, Japan); (Shinshu University, Japan); (Shinshu University, Japan)
- Shinshu University has been developing a visible light communication(VLC) system using Light Emitting Diode(LED) by modulating the light intensity. The data transmitting capability is demonstrated a few hundred Mbps for short distance and will be expected a few kbps for very long distance. ShindaiSat, a 35kg micro-satellite, is the first satellite to demonstrate the VLC between satellite and ground station and will be launched in 2014 by Japanese H-IIA launcher as a secondary payloads. This paper describes the outline of the satellite and some ground test results of VLC.
- 08:5012-2[Cancelled] Study about Visual Light Communication System for Nano-Satellite
- (Shinshu University, Japan)
- Shinshu University is now studying about visible light communication (VLC) system for satellite. Satellites are usually operated by radio communication and lack of frequency band and license application is a big burden for developers. So we are considering to use light communication for nano and micro (around 10kg or less) satellite. Light communication technology for large satellite (more than 100kg) is already verified and small satellite (50kg) system is now developed. Satellite resource is strict in nano-satellite, all on board components should be simple. And inexpensiveness and handiness are also important because it is often developed by one laboratory in a university. VLC system on ground by convolute signals on light is recently investigated. LED is robust than laser in the point of operational thermal rang and input voltage and easy to change output power considering transmission path, VLC is adopted for light source of nano-satellite light communication. Satellite has both uplink and downlink light channel in order to be concluded without radio. System description is as follows. -Downlink, transmission from satellite. --Beacon: Low speed Morse code signal. --Guide light: Multi beams which have IDs are sent outward from communication light bore sight. Ground station calculates satellite's pointing error compared the strength of each beam. --Communication light: Modulated communication light. Beam strength irradiation angle are controlled depending on the situation. -Downlink, reception at ground. The optical system is optimized for photon collection to receive signal at the expense of image accuracy. -Uplink, transmission from ground station. Brute force and conical scan light uplink are considered. -Uplink, reception at satellite. Less than 10cm diameter telescope receives signal from the ground. Arrayed detectors demodulate in parallel in order to calculate pointing error and S/N improvement. Current VLC system study and its attempt for satellite use are described in this paper.
- 09:1012-3Optical Communications in the Mexican Small Satellite Project
- (CICESE, Mexico); (CICESE, Mexico); (CICESE, Mexico); (CICESE, Mexico); (ITSON, Mexico); (VIVETEL, Mexico); (TELECOM ParisTech, France)
- Recent developments in small satellite stabilization and attitude control, as well as in formation flight dynamics, allow the implementation of optical inter-satellite links, in the new scenario of broadband-demanding applications.
Advances in the atmospheric telecommunications channel modeling, and in advanced modulation and coding formats, allow the implementation of optical satellite-to-ground links, taking advantage of the space-ground network techniques .
We first present the Mexican small satellites program aiming to reinforce regional competitivity and to enhance human resources formation in the aerospace sector, through the development of nanosatellite systems with advanced payloads, and the support elements for teaching and training in satellite technology .
We next present the current activities in the design and implementation of a satellite-to-ground optical communications payload consisting of an IR downlink optical transmitter for data communications, including both on board and optical ground station segments; including an uplink as a beacon for pointing purposes. This requires a very good stability and attitude capabilities from the nanosatellite, which we are developing in parallel, as well as the digital tools for signal distribution and processing.
Finally we present preliminary results at the laboratory level and short distance ground-to-ground testing of the on board and ground segments. As our program is intended both to provide a device ready to fly in a nanosatellite mission scenario, as well as an educational prototype, we mention the activities in the generation of instructional contents in order to create an interactive educational environment.
References 1. F. J. Mendieta, et al, "Optical Communications Payload for the Mexican NanoSatellite Project", Proc.ICSOS 2011, JPL, Santa Monica CA, USA, May 10-13, 2011 2. F. J. Mendieta, et al, "SENSAT: nano satellites with advanced payloads to promote human resources preparation in aerospace technologies in Mexico" UN/Austria/ESA Symposium on Small Satellite Programmes for Sustainable Development, Graz, Austria, September-2010.
- Flight Demonstrations IV
- Chair:Yoshihisa Takayama (National Institute of Information and Communications Technology, Japan)
- 09:3013-1The Alphasat GEO Laser Communication Terminal Flight Acceptance Tests
- (Tesat Spacecom, Germany); (Tesat-Spacecom, Germany); (Tesat Spacecom, Germany); (Tesat Spacecom, Germany); (Tesat Spacecom, Germany); (DLR, Germany); (DLR, Germany)
- The Alphasat GEO Laser Communication Terminal from Tesat Spacecom is currently in the final acceptance tests and will be delivered end of April 2012 for spacecraft integration to the the Alphasat mission.
The paper will summarize the design and the test results of the Alphasat GEO LCT.
- 09:5013-2Extending EDRS to Laser Communication from Space to Ground
- (ESA, The Netherlands); (European Space Agency, The Netherlands)
- In this paper we will be discussing various means of extending the laser communication of the European Data Relay Satellite (EDRS) system (between LEO and GEO satellites) to space to ground links. As the modulation scheme used in EDRS is coherent Binary Phase Shift Keying (BPSK) it is vulnerable to phase distortions caused by atmospheric turbulence. The design of an adaptive optics system, which can correct those wave-front distortions, will be described. In addition developments on a Differential Phase Shift Keying (DPSK) interferometer, which attempts to convert the phase modulation directly into amplitude modulation by interference of two successive bits will be described. Experimental results will be presented and the experience made with this new type of detection system discussed.
- Plenary: Pléiades Show
- Chair: Bruno Cugny (CNES, France)
- Closing Session
- Chairs: Bruno Cugny (CNES, France), Nikos Karafolas (ESA, Netherlands) & Errico Armandillo (ESA, Netherlands)