Free-Space Laser Communications: The Japanese Experience Morio Toyoshima Morio Toyoshima Morio Toyoshima Morio Toyoshima National Institute of Information and Communications Technology (NICT) Email: morio@nict.go.jp ECOC, Vienna, Austria ECOC, Vienna, Austria Sept. 24, 2009 Sept. 24, 2009 1
Outline • Introduction • Trends of data rates • Past and current optical space communication programs in Japan – ETS-VI/LCE program – OICETS/LUCE program – Development of digital coherent receivers – Development of Quantum Key Distribution (QKD) terminals • Japanese Data Relay Test Satellite (DRTS) at JAXA • About the wavelength selection • Concluding remarks 2 ECOC, Vienna, Austria, Sept. 24, 2009
Trends of data rate for Earth observation satellite 1.0E+10 TerraSAR-X 1.0E+09 Geo-Eye-1 Ikonos2 Spot5 Clark ALOS Landsat7 ERS2 Landsat4 EOS-PM1 bit/sec) Radarsat1 ERS1 1.0E+08 Landsat5 IRS-1C Envisat1 JERS1 JERS1 ADESO2 ADESO2 Data rate (bit Sunsat Sunsat ADEOS1 ADEOS1 Spot2 Landsat1 Spot3 Spot4 Spot1 GMS4 Terra Landsat2 Landsat3 IRS-1A GMS5 IRS P4 IRS-1B 1.0E+07 Resurs-01 N3 MOS1aMOS1b Elektro1 MeteosatSG TRMM MT-Sat Earth observation satellite (LEO) Orbview2 1.0E+06 DFH49 Earth observation satellite (GEO) GOES8 1.0E+05 1970 1975 1980 1985 1990 1995 2000 2005 2010 Launch year 3 ECOC, Vienna, Austria, Sept. 24, 2009
Trends of data rate for space laser comm. 1.0E+11 Digital coherent 1.0E+10 TerraSAR-X ate [bit/sec] NeLS 1.0E+09 OICETS 1.0E+08 Data rate SILEX SILEX 1.0E+07 1.0E+06 ETS-VI Space qualified 1.0E+05 Ground test 1.0E+04 1990 1995 2000 2005 2010 2015 Launch year 4 ECOC, Vienna, Austria, Sept. 24, 2009
R&D on optical space communications in NICT ARTEMIS ETS-VI GMS-2 GMS-3 GMS-4 OPALE(ESA) LCE GEO GEO-LEO GEO LEO GEO GEO- -GND GND Two Two- -way Laser Comm. way Laser Comm. Ar laser+ CO Ar laser+ CO 2 2 Laser Comm. Laser Comm. NeLS ( NICT) Optical Tracking Optical Tracking OICETS Development LUCE LUCE Laser Trasmission Laser Trasmission Laser Trasmission Laser Trasmission (JAXA) AJISAI, AJISAI, Experiment Experiment LEO LEO- -GND GND ADEOS, ADEOSII, ADEOS, ADEOSII, Two Two- -way way LRE, ALOS, ETS LRE, ALOS, ETS- -VIII VIII Laser Comm. Laser Comm. LEO Laser Ranging Laser Ranging LEO LEO- -GND GND 1.064 μ m 1.064 m Laser Tracking Laser Tracking GND NICT OGS (1.5m Telescope System) 1980 1990 2000 2010 5 ECOC, Vienna, Austria, Sept. 24, 2009
Laser communications experiment using ETS-VI satellite (Dec. 1994 - July 1996) • 1 Mbps IMDD bi-directional optical link experiment at a distance of ~40,000 km. • 22 kg, 60 W onboard equipment verification ETS-VI Laser Communication Equipment (LCE) NICT/CRL Optical Ground Station 6 ECOC, Vienna, Austria, Sept. 24, 2009
Uplink and downlink laser beams for the ETS-VI satellite Uplink laser beam from Downlink laser beam from the NICT/CRL ground station the ETS-VI satellite 7 ECOC, Vienna, Austria, Sept. 24, 2009
OICETS satellite system 1.8 m 1.8 m Optical Antenna 9.4 m 9.4 m Solar Array Paddle S-band Antennas Satellite size 0.78x1.1x1.5 m Mass 570 kg Mission life 1 year Altitude 610 km (circular) 8 Inclination 98 deg. ECOC, Vienna, Austria, Sept. 24, 2009 Courtesy of JAXA
Laser communication terminal Azimuth (AZ) axis 1.24 × 0.98 × 0.57 m Size Mass Approx. 140 kg Approx. 220 W Power EL Cable Rap Cable Wrap consumption (during communication) Optical Antenna Courtesy of JAXA ＨＣＥ EL Motor EL Encoder Elevation (EL) axis Inter Optics Part Cable Wrap AZ Cable Rap EL Gimbal Yoke LUCE (Laser Utilizing Communications Equipment) LUCE (Laser Utilizing Communications Equipment) AZ Motor/Encoder ECOC, Vienna, Austria, Sept. 24, 2009
Configuration of the experiment ESA/ARTEMIS OICETS/Kirari satellite Laser communication RF link (Satellite control) (Satellite control) DLR (Germany) ESA (Spain) NASA JPL (U.S.) JAXA Kirari operation center NICT (Japan) (Tsukuba Space Center) International cooperation International cooperation between 4 OGSs between 4 OGSs ECOC, Vienna, Austria, Sept. 24, 2009
OICETS scenario - Event - • Separation (changed) • Spin mode (changed) • Solar paddle deployment • Sun acquisition mode • • Earth acquisition mode Earth acquisition mode • Launch lock off • Trajectory control • 3-axis stabilized attitude control • Optical communication with ARTEMIS • Optical communication with NICT ground station 11 ECOC, Vienna, Austria, Sept. 24, 2009
Acquisition and tracking Wide CCD at FOV CCD FOV CCD Tx bench Tx bench Guide CCD at Telescope Rx bench 12 ECOC, Vienna, Austria, Sept. 24, 2009
Statistics of link establishment • Probability of success during Spacecraft/ operation error Link established all the experiments 7% 32% – NICT: 49.1 % Cloud – NASA JPL: 57.1 % 25% – DLR: 60.0 % – ESA: 88.9 % • Total probability of success between Earth and space: Link established Rain (interrupted by – 1-[(1-0.491)x(1-0.571) 21% clouds) x(1-0.60)x(1-0.889)] = 0.9903 12% Link established through thick • Four OSGs combination will clouds 5% help to download massive data Statistics of link establishment at NICT from space with the probability of 99%. 13 ECOC, Vienna, Austria, Sept. 24, 2009
Digital coherent receiver aiming for free-space laser communications • Interoperability between IMDD and coherent technologies (1.064 & 1.5 μ m) which allow us to communicate with ESA’s coherent terminals • Signal fading caused by atmospheric turbulence can be compensated by the real-time digital signal processing (DSP). • No optical PLL because commercially available local lasers can be used as free-running conditions. Optical devices at 1.5 μ m are available. • Mod. formats: - IMDD - Coherent (1.0 & 1.5 μ m) 14 ECOC, Vienna, Austria, Sept. 24, 2009
Development of real-time digital coherent receiver ~ Implementation of FPGAs ~ • 3 Gbps BPSK real-time coherent receiver in 2007 – 2xADC: NS ADC083000 – FPGA: Xilinx Virtex-4/FX100 • 6 Gbps BPSK real-time coherent receiver in 2008 – 4xADC: NS ADC083000 – 2xFPGA: Xilinx Virtex-4 & Virtex-5 – 2xFPGA: Xilinx Virtex-4 & Virtex-5 • Dual wavelengths free-space optical 90 degree hybrid – Two wavelengths (1.064 &1.5 μ m) can be received without no reconfiguration. – High I/Q extinction ratio: >50 dB 15 ECOC, Vienna, Austria, Sept. 24, 2009
Development of QKD terminals ~1-km free-space QKD experiments~ Hotel Mets Kokubunji Hotel Mets Kokubunji Bob Bob NICT NICT NICT NICT Alice Alice Alice Alice ~1km 1km Alice Alice JR Kokubunji JR Kokubunji Bob station station 16 ECOC, Vienna, Austria, Sept. 24, 2009
Japanese Data Relay Satellite at JAXA Data Relay Satellite Data Relay Test Satellite “Kodama” Low earth orbit 1~2 DRTSs will be in operation. 1~2 DRTSs will be in operation. “ALOS” “ALOS” ALOS2 ALOS2 Wavelength:1.064 um ALOS3 Data rate: 2.5 Gbps R&D of next generation optical intersatellite technology Mod: Homodyne BPSK PLL: Optical PLL Optical terminal can be compact and several ones can be onboard GEO. Development Research http://www.jaxa.jp/press/2009/09/20090909_sac_oicets.pdf ( in Japanese) 17 ECOC, Vienna, Austria, Sept. 24, 2009
Trends of data rate and the receiver sensitivity 1.0E+15 WDM 1550 nm Technique 1.0E+12 ata rate [bit/s] 1064 or 1550 nm DPSK(2003) RZ-DPSK(2004) RZ-AMI(2003) Digital coherent DPSK(2008) NeLS TerraSAR-X 1.0E+09 1.0E+09 Da 800 nm OICETS SILEX Classical limit ETS-VI (Shannon limit) 1.0E+06 Space qualified Ground test 1.0E+03 1.0E+00 1.0E+01 1.0E+02 1.0E+03 1.0E+04 Sensitivity@BER=10 -6 or 10 -9 [photons/bit] 18 ECOC, Vienna, Austria, Sept. 24, 2009
Concluding Remarks • ETS-VI/LCE successfully demonstrated the ground-to- satellite optical communication experiments. • OICETS/LUCE succeeded to establish the inter-satellite and ground-to-satellite links. The precise acquisition and pointing technology necessary for a LEO to GEO link was confirmed. • International cooperation is important for site diversity. • Current R&D was presented related to the digital coherent receiver and the QKD experiments. • For the wavelength selection, 1.064 μ m will be used at this moment. However, 1.5 μ m technology will be the next lead for the higher data demands even in space laser communications. 19 ECOC, Vienna, Austria, Sept. 24, 2009
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