Page 1
Free-Space Laser Communications: The Japanese Experience
Morio ToyoshimaMorio Toyoshima
1
Morio ToyoshimaMorio Toyoshima
National Institute of Information and Communications Technology (NICT)
Email: [email protected]
ECOC, Vienna, AustriaECOC, Vienna, AustriaSept. 24, 2009Sept. 24, 2009
Page 2
Outline• Introduction• Trends of data rates• Past and current optical space communication programs
in Japan– ETS-VI/LCE program
ECOC, Vienna, Austria, Sept. 24, 2009
– 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
Page 3
ERS1 Radarsat1Envisat1
ERS2Spot5
IRS-1CSunsatJERS1
ADEOS1ADESO2
ALOSEOS-PM1Landsat4
Landsat5
Landsat7
Ikonos2Clark
Geo-Eye-1
TerraSAR-X
1.0E+08
1.0E+09
1.0E+10
bit/s
ec)
Trends of data rate for Earth observation satellite
ECOC, Vienna, Austria, Sept. 24, 2009
Orbview2
Spot1Spot2
Spot3 Spot4IRS-1A
IRS-1B IRS P4
SunsatJERS1ADEOS1
ADESO2
MOS1aMOS1b Resurs-01 N3
Landsat1
Landsat2Landsat3 Terra
TRMM
GOES8
MeteosatSG
DFH49
GMS4GMS5
MT-Sat
Elektro1
1.0E+05
1.0E+06
1.0E+07
1970 1975 1980 1985 1990 1995 2000 2005 2010
Dat
a ra
te (
bit
Launch year
Earth observation satellite (LEO)
Earth observation satellite (GEO)
3
Page 4
SILEX
OICETS
TerraSAR-X
Digitalcoherent
NeLS
1.0E+08
1.0E+09
1.0E+10
1.0E+11at
e [b
it/se
c]
Trends of data rate for space laser comm.
ECOC, Vienna, Austria, Sept. 24, 20094
SILEX
ETS-VI
1.0E+04
1.0E+05
1.0E+06
1.0E+07
1990 1995 2000 2005 2010 2015
Launch year
Dat
a ra
te
Space qualifiedGround test
Page 5
R&D on optical space communications in NICTETS-VI
LCEARTEMIS
OPALE(ESA)
GEO
GMS-2 GMS-3 GMS-4
Laser TrasmissionLaser Trasmission
ArAr laser+ COlaser+ CO22
OICETSLUCE
Optical TrackingOptical Tracking
GEOGEO--GNDGNDLaser Comm.Laser Comm.
GEOGEO--LEOLEOTwoTwo--way Laser Comm.way Laser Comm.
NeLS (NICT)Development
ECOC, Vienna, Austria, Sept. 24, 20095
1990 2000 2010
LEO
GND
1980
Laser TrasmissionLaser TrasmissionExperimentExperiment
Laser RangingLaser Ranging
LUCE(JAXA)LEOLEO--GNDGND
TwoTwo--way way Laser Comm.Laser Comm.
NICT OGS (1.5m Telescope System)
AJISAI,AJISAI,ADEOS, ADEOSII,ADEOS, ADEOSII,LRE, ALOS, ETSLRE, ALOS, ETS--VIIIVIII
LEOLEO--GNDGND1.064 1.064 μμm m Laser TrackingLaser Tracking
Page 6
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
ECOC, Vienna, Austria, Sept. 24, 2009
NICT/CRL Optical Ground Station
ETS-VI
Laser Communication Equipment (LCE)
6
Page 7
Uplink and downlink laser beams for the ETS-VI satellite
ECOC, Vienna, Austria, Sept. 24, 2009
Uplink laser beam from the NICT/CRL ground station
Downlink laser beam fromthe ETS-VI satellite
7
Page 8
OICETS satellite system
Optical Antenna
1.8 m1.8 m
ECOC, Vienna, Austria, Sept. 24, 20098
Solar Array PaddleS-band Antennas
Satellite size 0.78x1.1x1.5 m
Mass 570 kg
Mission life 1 year
Altitude 610 km (circular)
Inclination 98 deg.
9.4 m9.4 m
Courtesy of JAXA
Page 9
Laser communication terminal
Optical Antenna
EL Cable RapCable Wrap
HCE
Azimuth (AZ) axis
Size 1.24×0.98×0.57 m
Mass Approx. 140 kg
Power consumption
Approx. 220 W
(during communication)
Courtesy of JAXA
ECOC, Vienna, Austria, Sept. 24, 2009
Elevation (EL) axis
EL Gimbal Yoke
AZ Motor/Encoder
AZ Cable Rap
Inter Optics Part
EL Encoder
EL Motor
Cable Wrap
LUCE (Laser Utilizing Communications Equipment)LUCE (Laser Utilizing Communications Equipment)
Page 10
Configuration of the experiment
Laser communication RF link (Satellite control)
ESA/ARTEMISOICETS/Kirari satellite
ECOC, Vienna, Austria, Sept. 24, 2009
NICT (Japan) JAXA Kirari operation center(Tsukuba Space Center)
(Satellite control)
NASA JPL (U.S.)
DLR (Germany)
ESA (Spain)
International cooperation International cooperation between 4 OGSsbetween 4 OGSs
Page 11
OICETS scenario
- Event -• Separation (changed)• Spin mode (changed)• Solar paddle deployment• Sun acquisition mode• Earth acquisition mode
ECOC, Vienna, Austria, Sept. 24, 2009
• Earth acquisition mode• Launch lock off• Trajectory control• 3-axis stabilized attitude
control• Optical communication
with ARTEMIS• Optical communication
with NICT ground station
11
Page 12
Acquisition and tracking
Wide FOV CCD
CCD at Tx bench
ECOC, Vienna, Austria, Sept. 24, 200912
FOV CCD Tx bench
Guide Telescope
CCD at Rx bench
Page 13
Statistics of link establishment
Link established32%
Cloud25%
Spacecraft/operation error
7%
• Probability of success during all the experiments– NICT: 49.1 %– NASA JPL: 57.1 %– DLR: 60.0 %– ESA: 88.9 %
ECOC, Vienna, Austria, Sept. 24, 200913
Link established (interrupted by
clouds)12%Link established
through thick clouds
5%
Rain21%
• Total probability of success between Earth and space:– 1-[(1-0.491)x(1-0.571)
x(1-0.60)x(1-0.889)] = 0.9903
• Four OSGs combination will help to download massive data from space with the probability of 99%.
Statistics of link establishment at NICT
Page 14
Digital coherent receiver aiming for free-space laser communications
• Interoperability between IMDD and coherent technologies (1.064 & 1.5 μm) 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 μm are available.
ECOC, Vienna, Austria, Sept. 24, 200914
Mod. formats: - IMDD- Coherent (1.0 & 1.5 μm)
Page 15
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
ECOC, Vienna, Austria, Sept. 24, 200915
– 2xFPGA: Xilinx Virtex-4 & Virtex-5
• Dual wavelengths free-space optical 90 degree hybrid– Two wavelengths (1.064 &1.5 μm) can be received without no
reconfiguration.– High I/Q extinction ratio: >50 dB
Page 16
Development of QKD terminals~1-km free-space QKD experiments~
AliceAlice
NICTNICT
Hotel Mets KokubunjiHotel Mets Kokubunji
NICTNICT
BobBob
ECOC, Vienna, Austria, Sept. 24, 200916
AliceAlice
Bob
AliceAlice~~1km1km
JR KokubunjiJR Kokubunjistationstation
Page 17
Japanese Data Relay Satellite at JAXA
Data Relay Test Satellite “Kodama”
Data Relay Satellite
“ALOS” ALOS2
Low earth orbit1~2 DRTSs will be in operation.
ECOC, Vienna, Austria, Sept. 24, 200917
http://www.jaxa.jp/press/2009/09/20090909_sac_oicets.pdf ( in Japanese)
“ALOS” ALOS2
ALOS3
Research Development
R&D of next generation optical intersatellite technology
Optical terminal can be compact and several ones can be onboard GEO.
Wavelength:1.064 umData rate: 2.5 GbpsMod: Homodyne BPSKPLL: Optical PLL
1~2 DRTSs will be in operation.
Page 18
Trends of data rate and the receiver sensitivity
TerraSAR-X
Digital coherentNeLS
DPSK(2003)RZ-AMI(2003)RZ-DPSK(2004)
DPSK(2008)
1.0E+09
1.0E+12
1.0E+15at
a ra
te [b
it/s]
WDM Technique
1064 or 1550 nm
1550 nm
ECOC, Vienna, Austria, Sept. 24, 200918
ETS-VIOICETS SILEX
1.0E+03
1.0E+06
1.0E+09
1.0E+00 1.0E+01 1.0E+02 1.0E+03 1.0E+04
Da
Sensitivity@BER=10-6 or 10-9 [photons/bit]
Space qualified
Ground test
Classical limit(Shannon limit)
800 nm
Page 19
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.
ECOC, Vienna, Austria, Sept. 24, 2009
• 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 μm will be used at
this moment. However, 1.5 μm technology will be the next lead for the higher data demands even in space laser communications.
19