Deep Space Optical Communications Book

Foreword     xvii
Preface     xix
Acknowledgments     xxiii
Contributors     xxv
Introduction   James R. Lesh     1
Motivation for Increased Communications     1
History of JPL Optical Communications Activities     5
Component/Subsystem Technologies     7
Laser Transmitters     8
Spacecraft Telescopes     10
Acquisition, Tracking, and Pointing     10
Detectors     12
Filters     14
Error Correction Coding     14
Flight Terminal Developments     16
Optical Transceiver Package (OPTRANSPAC)     16
Optical Communications Demonstrator (OCD)     17
Lasercom Test and Evaluation Station (LTES)     19
X2000 Flight Terminal     20
International Space Station Flight Terminal     22
Reception System and Network Studies     23
Ground Telescope Cost Model     24
Deep Space Optical Reception Antenna (DSORA)     25
Deep Space Relay Satellite System (DSRSS) Studies     26
Ground-Based Antenna Technology Study (GBATS)     27
Advanced Communications Benefits Study (ACBS)     28
Earth Orbit Optical Reception Terminal (EOORT) Study     29
EOORT Hybrid Study     30
Spherical Primary Ground Telescope     30
Space-Based versus Ground-Based Reception Trades     31
Atmospheric Transmission     34
Background Studies     36
Analysis Tools     37
System-Level Studies     38
Venus Radar Mapping (VRM) Mission Study     38
Synthetic Aperture Radar-C (SIR-C) Freeflyer     38
ER-2 to Ground Study     39
Thousand Astronomical Unit (TAU) Mission and Interstellar Mission Studies     40
System-Level Demonstrations     41
Galileo Optical Experiment (GOPEX)     41
Compensated Earth-Moon-Earth Retro-Reflector Laser Link (CEMERLL)     43
Ground/Orbiter Lasercomm Demonstration (GOLD)     44
Ground-Ground Demonstrations     47
Other Telecommunication Functions     50
Opto-Metric Navigation     50
Light Science     51
The Future     52
Optical Communications Telescope Facility (OCTL)     52
Unmanned Arial Vehicle (UAV)-Ground Demonstration     52
Adaptive Optics     53
Optical Receiver and Dynamic Detector Array      55
Alternate Ground-Reception Systems     56
Mars Laser Communication Demonstration     57
Summary of Following Chapters     58
References     60
Link and System Design   Chien-Chung Chen     83
Overview of Deep-Space Lasercom Link     85
Communications Link Design     87
Link Equation and Receive Signal Power     89
Optical-Receiver Sensitivity     91
Photon Detection Sensitivity     95
Modulation Format     95
Background Noise Control     96
Link Design Trades     98
Operating Wavelength     98
Transmit Power and Size of Transmit and Receive Apertures     99
Receiver Optical Bandwidth and Field of View versus Signal Throughput     99
Modulation and Coding     100
Communications Link Budget     100
Link Availability Considerations     100
Short-Term Data Outages     101
Weather-Induced Outages     103
Other Long-Term Outages     104
Critical-Mission-Phase Coverage     106
Beam Pointing and Tracking     106
Downlink Beam Pointing     107
Jitter Isolation and Rejection      107
Precision Beam Pointing and Point Ahead     108
Uplink Beam Pointing     110
Pointing Acquisition     111
Other Design Drivers and Considerations     113
System Mass and Power     113
Impact on Spacecraft Design     114
Laser Safety     115
Summary     115
References     118
The Atmospheric Channel   Abhijit Biswas   Sabino Piazzolla     121
Cloud Coverage Statistics     123
National Climatic Data Center Data Set     124
Single-Site and Two-Site Diversity Statistics     126
Three-Site Diversity     130
NCDC Analysis Conclusion     135
Cloud Coverage Statistics by Satellite Data Observation     137
Atmospheric Transmittance and Sky Radiance     140
Atmospheric Transmittance     140
Molecular Absorption and Scattering     141
Aerosol Absorption and Scattering     145
Atmospheric Attenuation Statistics     148
Sky Radiance     151
Sky Radiance Statistics     156
Point Sources of Background Radiation     159
Atmospheric Issues on Ground Telescope Site Selection for an Optical Deep Space Network     169
Optical Deep Space Network     169
Data Rate/BER of a Mission     174
Telescope Site Location     174
Network Continuity and Peaks     178
Laser Propagation Through the Turbulent Atmosphere     184
Atmospheric Turbulence     184
Atmospheric "Seeing" Effects     190
Optical Scintillation or Irradiance Fluctuations     198
Atmospheric Turbulence Induced Angle of Arrival     204
References     207
Optical Modulation and Coding   Samuel J. Dolinar   Jon Hamkins   Bruce E. Moision   Victor A. Vilnrotter     215
Introduction     215
Statistical Models for the Detected Optical Field     219
Quantum Models of the Optical Field     219
Quantization of the Electric Field     220
The Coherent State Representation of a Single Field Mode     222
Quantum Representation of Thermal Noise     223
Quantum Representation of Signal Plus Thermal Noise     223
Statistical Models for Direct Detection     224
The Poisson Channel Model for Ideal Photodetectors or Ideal PMTs     225
The McIntyre-Conradi Model for APD Detectors     226
The Webb, McIntyre, and Conradi Approximation to the McIntyre-Conradi Model     228
The WMC Plus Gaussian Approximation     229
Additive White Gaussian Noise Approximation     229
Summary of Statistical Models     231
Modulation Formats     231
On-Off Keying (OOK)     233
Pulse-Position Modulation (PPM)     234
Differential PPM (DPPM)     235
Overlapping PPM (OPPM)     236
Wavelength Shift Keying (WSK)     237
Combined PPM and WSK     237
Rate Limits Imposed by Constraints on Modulation     238
Shannon Capacity     239
Characterizing Capacity: Fixed Duration Edges     240
Characterizing Capacity: Variable Duration Edges     241
Characterizing Capacity: Probabilistic Characterization     241
Characterizing Capacity: Energy Efficiency     243
Constraints     243
Dead Time     244
Runlength     245
Modulation Codes     245
M-ary PPM with Deadtime     246
M-ary DPPM with Deadtime     247
Synchronous Variable-Length Codes     248
Performance of Uncoded Optical Modulations     250
Direct Detection of OOK on the Poisson Channel     251
Direct Detection of PPM     252
Poisson Channel     254
AWGN Channel     258
Direct Detection of Combined PPM and WSK     260
Performance of Modulations Using Receivers Based on Quantum Detection Theory     260
Receivers Based on Quantum Detection Theory     260
Performance of Representative Modulations     264
Optical Channel Capacity     268
Capacity of the PPM Channel: General Formulas     269
Capacity of Soft-Decision PPM: Specific Channel Models     270
Poisson Channel     270
AWGN Channel     271
Hard-Decision Versus Soft-Decision Capacity     272
Losses Due to Using PPM     273
Capacity of the Binary Channel with Quantum Detection     275
Channel Codes for Optical Modulations     277
Reed-Solomon Codes     278
Turbo and Turbo-Like Codes for Optical Modulations     279
Parallel Concatenated (Turbo) Codes     279
Serially Concatenated Codes with Iterative Decoding     280
Performance of Coded Optical Modulations     281
Parameter Selection     281
Estimating Performance     284
Reed-Solomon Codes      284
Iterative Codes     286
Achievable Data Rates Versus Average Signal Power     286
References     289
Flight Transceiver   Hamid Hemmati   Gerardo G. Ortiz   William T. Roberts   Malcolm W. Wright   Shinhak Lee     301
Optomechanical Subsystem   Hamid Hemmati     301
Introduction     301
Optical Beam Paths     302
Optical Design Requirements, Design Drivers, and Challenges     304
Optical Design Drivers and Approaches     306
Transmit-Receive-Isolation     307
Stray-Light Control     309
Operation at Small Sun Angles     309
Surface Cleanliness Requirements     310
Transmission, Alignment, and Wavefront Quality Budgets     310
Efficient Coupling of Lasers to Obscured Telescopes     311
Axicon Optical Element     311
Sub-Aperture Illumination     311
Prism Beam Slicer     312
Beam Splitter/Combiner     313
Structure, Materials, and Structural Analysis     314
Use of Fiber Optics     316
Star-Tracker Optics for Acquisition and Tracking     316
Thermal Management      317
Optical System Design Example     317
Afocal Fore-Optics     317
Receiver Channel     317
Stellar Reference Channel     322
Align and Transmit Channels     324
Folded Layouts     325
Tolerance Sensitivity Analysis     326
Thermal Soak Sensitivity Analysis     328
Solid Model of System     329
Laser Transmitter   Hamid Hemmati     331
Introduction     331
Requirements and Challenges     333
Candidate Laser Transmitter Sources     337
Pulsed Laser Transmitters     338
Fiber-Waveguide Amplifiers     340
Bulk-Crystal Amplifiers     342
Semiconductor Optical Amplifiers     345
Lasers for Coherent Communications     346
Laser Modulators     346
Efficiency     347
Laser Timing Jitter Control     348
Jitter Control Options     348
Redundancy     350
Thermal Management     350
Deep-Space Acquisition, Tracking, and Pointing   Gerardo G. Ortiz   Shinhak Lee     351
Unique Challenges of Deep Space Optical Beam Pointing     351
State-of-the-Art ATP Performance     352
Link Overview and System Requirements     353
Pointing Requirement     353
Pointing-Error Budget Allocations     357
ATP System     357
Pointing Knowledge Reference Sources     357
Pointing System Architecture     360
Design Considerations     363
Cooperative Beacon (Ground Laser) Tracking     373
Noncooperative Beacon Tracking     374
Earth Tracker-Visible Spectrum     375
Star Tracker     382
Earth Tracker-Long Wavelength Infrared Band     391
ATP Technology Demonstrations     399
Reduced Complexity ATP Architecture     399
Centroiding Algorithms-Spot Model Method     401
High Bandwidth, Windowing, CCD-Based Camera     407
Accelerometer-Assisted Beacon Tracking     412
Flight Qualification   Hamid Hemmati   William T. Roberts   Malcolm W. Wright     419
Introduction     419
Approaches to Flight Qualification     420
Flight Qualification of Electronics and Opto-Electronic Subsystem     422
MIL-PRF-19500     422
MIL STD 750     422
MIL STD 883      422
Telcordia     423
NASA Electronics Parts and Packaging (NEPP)     423
Number of Test Units     423
Space Environments     425
Environmental Requirements     425
Ionizing Radiation     426
Vibration Environment     428
Mechanical, Thermal, and Pyro Shock Environment     429
Thermal Gradients Environment     429
Depressurization Environment     430
Electric and Magnetic Field Environment     430
Outgassing     431
Flight Qualification of Detectors     431
Flight Qualification Procedures     432
Detector Radiation Testing     440
Flight Qualification of Laser Systems     443
Past Laser Systems Flown in Space     444
Design of Semiconductor Lasers for High Reliability Applications     447
Degradation Mechanisms     448
Qualification Process for Lasers     449
Flight Qualification of Optics     454
References     454
Earth Terminal Architectures   Keith E. Wilson   Abhijit Biswas   Andrew A. Gray   Victor A. Vilnrotter   Chi-Wung Lau   Mera Srinivasan   William H. Farr      467
Introduction   Keith E. Wilson     467
Single-Station Downlink Reception and Uplink Transmission   Keith E. Wilson     469
Introduction     469
Deep-Space Optical Ground Receivers     470
Mitigating Cloud Cover and Sky Background Effects at the Receiver     472
Daytime Sky Background Effects     475
Earth-Orbiting and Airborne Receivers     476
Uplink Beacon and Command     476
Techniques for Mitigating Atmospheric Effects     482
Adaptive Optics     484
Multiple-Beam Propagation     486
Safe Laser Beam Propagation into Space     488
Concept Validation Experiments Supporting Future Deep-Space Optical links     493
Conclusion     514
Optical-Array Receivers for Deep-Space Communication   Victor A. Vilnrotter   Chi-Wung Lau   Meera Srinivasan     516
Introduction     516
The Optical-Array Receiver Concept     516
Aperture-Plane Expansions     519
Array Receiver Performance     527
Conclusions     540
Photodetectors     541
Single-Element Detectors   Abhijit Biswas   William H. Farr      541
Deep-Space Detector Requirements and Challenges     541
Detector System Dependencies     544
Detectors for Deep-Space Communications     545
Focal-Plane Detector Arrays for Communication Through Turbulence   Victor A. Vilnrotter   Meera Srinivasan     551
Introduction     551
Optical Direct Detection with Focal-Plane Arrays     553
Numerical Results     562
Summary And Conclusions     566
Receiver Electronics   Andrew A. Gray   Victor A. Vilnrotter   Meera Srinivasan     567
Introduction     567
Introduction to Discrete-Time Demodulator Architectures     571
Discrete-Time Synchronization and Post-Detection Filtering Overview     572
Discrete-Time Post-Detection Filtering     573
Slot and Symbol Synchronization and Decision Processing     580
Discrete-Time Demodulator Variations     584
Discrete-Time Demodulator with Time-Varying Post-Detection Filter     585
Parallel Discrete-Time Demodulator Architectures     589
Asynchronous Discrete-Time Processing     592
Parallel Discrete-Time Demodulator Architectures     603
Simple Example Architecture      603
Performance with a Simple Optical Channel Model     606
Evolved Parallel Architectures     608
Primary System Models and Parameters     616
Conclusion and Future Work     618
References     626
Future Prospects and Applications   Hamid Hemmati   Abhijit Biswas     643
Current and Upcoming Projects in the United States, Europe, and Japan     643
LUCE (Laser Utilizing Communications Experiment)     643
Mars Laser-Communication Demonstrator (MLCD)     644
Airborne and Spaceborne Receivers     646
Advantages of Airborne and Spaceborne Receivers     646
Disadvantages of Airborne and Spaceborne Receivers     647
Airborne Terminals     648
Balloons     648
Airships     649
Airplanes     649
Spaceborne Receiver Terminals     650
Alternative Receiver Sites     650
Light Science     650
Light-Propagation Experiments     651
Occultation Experiments to Probe Planetary Atmospheres, Rings, Ionospheres, Magnetic Fields, and the Interplanetary Medium     651
Atmospheric Occultations     652
Ring-Investigation Experiments     652
Enhanced Knowledge of Solar-System-Object Masses and Gravitational Fields, Sizes, Shapes, and Surface Features     652
Improved Knowledge of Solar-System Body Properties     653
Optical Reference-Frame Ties     653
Tests of the Fundamental Theories: General Relativity, Gravitational Waves, Unified Field Theories, Astrophysics, and Cosmology     653
Tests of General Relativity and Unified Field Theories, Astrophysics, and Cosmology     654
Effects of Charged Particles on Electromagnetic Wave Propagation, Including Test of 1/f Hypothesis     654
Enhanced Solar-System Ephemerides     654
Science Benefits of Remote Optical Tracking: Ephemeris Improvement     655
Applications of Coherent Laser Communications Technology     656
Conclusions     657
References     657