Details

Coherent Laser Beam Combining

1. Aufl.

von: Arnaud Brignon
147,99 €
Verlag:	Wiley-VCH
Format:	PDF
Veröffentl.:	08.07.2013
ISBN/EAN:	9783527652808
Sprache:	englisch
Anzahl Seiten:	498

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Titelbeschreibung

Laser beam combining techniques allow increasing the power of lasers far beyond what it is possible to obtain from a single conventional laser.One step further, coherent beam combining (CBC) also helps to maintain the very unique properties of the laser emission with respect to its spectral and spatial properties. Such lasers are of major interest for many applications, including industrial, environmental, defense, and scientific applications. Recently, significant progress has beenmade in coherent beam combining lasers, with a total output power of 100 kW already achieved. Scaling analysis indicates that further increase of output power with excellent beam quality is feasible by using existing state-of-the-art lasers. Thus, the knowledge of coherent beam combining techniques will become crucial for the design of next-generation highpower lasers. The purpose of this book is to present the more recent concepts of coherent beam combining by world leader teams in the field.

Inhaltsverzeichnis

Preface XV Acronyms XVII List of Contributors XXI Part One: Coherent Combining with Active Phase Control 1 1 Engineering of Coherently Combined, High-Power Laser Systems 3 Gregory D. Goodno and Joshua E. Rothenberg 1.1 Introduction 3 1.2 Coherent Beam Combining System Requirements 5 1.3 Active Phase-Locking Controls 8 1.3.1 Optical Heterodyne Detection 11 1.3.2 Synchronous Multidither 13 1.3.3 Hill Climbing 14 1.4 Geometric Beam Combining 14 1.4.1 Tiled Aperture Combiners 15 1.4.2 Filled Aperture Combiners Using Diffractive Optical Elements 16 1.4.2.1 Overview of DOE Combiners 17 1.4.2.2 DOE Design and Fabrication 18 1.4.2.3 DOE Thermal and Spectral Sensitivity 20 1.5 High-Power Coherent Beam Combining Demonstrations 21 1.5.1 Coherent Beam Combining of Zigzag Slab Lasers 22 1.5.2 Coherent Beam Combining of Fiber Lasers 26 1.5.2.1 Phase Locking of Nonlinear Fiber Amplifiers 26 1.5.2.2 Path Length Matching with Broad Linewidths 30 1.5.2.3 Diffractive CBC of High-Power Fibers 31 1.5.2.4 CBC of Tm Fibers at 2 mm 37 1.6 Conclusion 39 Acknowledgments 40 References 40 2 Coherent Beam Combining of Fiber Amplifiers via LOCSET 45 Angel Flores, Benjamin Pulford, Craig Robin, Chunte A. Lu, and Thomas M. Shay 2.1 Introduction 45 2.1.1 Beam Combination Architectures 46 2.1.2 Active and Passive Coherent Beam Combining 47 2.2 Locking of Optical Coherence by Single-Detector Electronic-Frequency Tagging 48 2.2.1 LOCSET Theory 49 2.2.2 Self-Referenced LOCSET 50 2.2.2.1 Photocurrent Signal 50 2.2.2.2 LOCSET Demodulation 53 2.2.3 Self-Synchronous LOCSET 55 2.3 LOCSET Phase Error and Channel Scalability 55 2.3.1 LOCSET Beam Combining and Phase Error Analysis 55 2.3.2 In-Phase and Quadrature-Phase Error Analysis 56 2.3.3 Two-Channel Beam Combining 58 2.3.4 16-Channel Beam Combining 60 2.3.5 32-Channel Beam Combining 62 2.4 LOCSET High-Power Beam Combining 63 2.4.1 Kilowatt-Scale Coherent Beam Combining of Silica Fiber Lasers 64 2.4.2 Kilowatt-Scale Coherent Beam Combining of Photonic Crystal Fiber Amplifiers 67 2.5 Conclusion 71 References 71 3 Kilowatt Coherent Beam Combining of High-Power Fiber Amplifiers Using Single-Frequency Dithering Techniques 75 Zejin Liu, Pu Zhou, Xiaolin Wang, Yanxing Ma, and Xiaojun Xu 3.1 Introduction 75 3.1.1 Brief History of Coherent Beam Combining 75 3.1.2 Coherent Beam Combining: State of the Art 76 3.1.3 Key Technologies for Coherent Beam Combining 77 3.2 Single-Frequency Dithering Technique 78 3.2.1 Theory of Single-Frequency Dithering Technique 78 3.2.2 Kilowatt Coherent Beam Combining of High-Power Fiber Amplifiers Using Single-Frequency Dithering Technique 85 3.2.3 Coherent Polarization Beam Combining of Four High-Power Fiber Amplifiers Using Single-Frequency Dithering Technique 88 3.2.4 Target-in-the-Loop Coherent Beam Combination of Fiber Lasers Based on Single-Frequency Dithering Technique 91 3.3 Sine–Cosine Single-Frequency Dithering Technique 94 3.3.1 Theory of Sine–Cosine Single-Frequency Dithering Technique 94 3.3.2 Coherent Beam Combining of Nine Beams Using Sine–Cosine Single-Frequency Dithering Technique 97 3.4 Summary 99 References 100 4 Active Coherent Combination Using Hill Climbing-Based Algorithms for Fiber and Semiconductor Amplifiers 103 Shawn Redmond, Kevin Creedon, Tso Y. Fan, Antonio Sanchez-Rubio, Charles Yu, and Joseph Donnelly 4.1 Introduction to Hill Climbing Control Algorithms for Active Phase Control 103 4.1.1 Conventional SPGD-Based Control Algorithm for Active Phase Control 104 4.1.2 Orthonormal Dither-Based Control Algorithm 106 4.1.3 Multiple Detector-Based Control Algorithm 114 4.2 Applications of Active Phase Control Using Hill Climbing Control Algorithms 117 4.2.1 Semiconductor Amplifier Active Coherent Combination 117 4.2.1.1 Introduction to SCOWA Semiconductor Waveguide and Phase Control 118 4.2.1.2 Tiled Array Beam Combination 120 4.2.1.3 Single-Beam Active Coherent Combination Using Diffractive Optical Elements 125 4.2.2 Fiber Amplifier Active Coherent Combination 128 4.2.2.1 Introduction to Fiber Amplifier Active Beam Combination Architectures 128 4.2.2.2 Tiled Array Beam Combination 129 4.2.2.3 Single-Beam Active Coherent Combination Using Diffractive Optical Elements 133 4.3 Summary 134 Disclaimer 134 References 135 5 Collective Techniques for Coherent Beam Combining of Fiber Amplifiers 137 Arnaud Brignon, Jerome Bourderionnet, Cindy Bellanger, and Jerome Primot 5.1 Introduction 137 5.2 The Tiled Arrangement 138 5.2.1 Calculation of the Far-Field Intensity Pattern 139 5.2.2 Influence of Design Parameters on the Combining Efficiency 141 5.2.2.1 Impact of the Near Field Arrangement 141 5.2.2.2 Impact of Collimation System Design and Errors 143 5.2.2.3 Impact of Phase Error 145 5.2.2.4 Impact of Power Dispersion 146 5.2.3 Beam Steering 146 5.3 Key Elements for Active Coherent Beam Combining of a Large Number of Fibers 147 5.3.1 Collimated Fiber Array 148 5.3.2 Collective Phase Measurement Technique 151 5.3.2.1 Principle of the Measurement 152 5.3.2.2 Implementation in the Experimental Setup 153 5.3.2.3 Phase Retrieval Techniques 153 5.3.3 Phase Modulators 155 5.4 Beam Combining of 64 Fibers with Active Phase Control 156 5.5 Beam Combining by Digital Holography 158 5.5.1 Principle 159 5.5.2 Experimental Demonstration 161 5.6 Conclusion 163 Acknowledgments 164 References 164 6 Coherent Beam Combining and Atmospheric Compensation with Adaptive Fiber Array Systems 167 Mikhail Vorontsov, Thomas Weyrauch, Svetlana Lachinova, Thomas Ryan, Andrew Deck, Micah Gatz, Vladimir Paramonov, and Gary Carhart 6.1 Introduction 167 6.2 Fiber Array Engineering 168 6.3 Turbulence-Induced Phase Aberration Compensation with Fiber Array-Integrated Piston and Tip–Tilt Control 173 6.4 Target Plane Phase Locking of a Coherent Fiber Array on an Unresolved Target 175 6.4.1 Fiber Array Control System Engineering: Issues and Considerations 175 6.4.2 SPGD-Based Coherent Beam Combining: Round-Trip Propagation Time Issue 176 6.4.3 Coherent Beam Combining at an Unresolved Target over 7 km Distance 178 6.5 Target Plane Phase Locking for Resolved Targets 182 6.5.1 Speckle Metric Optimization-Based Phase Locking 183 6.5.2 Speckle Metrics 184 6.5.3 Experimental Evaluation of Speckle Metric-Based Phase Locking 186 6.6 Conclusion 188 Acknowledgments 189 References 189 7 Refractive Index Changes in Rare Earth-Doped Optical Fibers and Their Applications in All-Fiber Coherent Beam Combining 193 Andrei Fotiadi, Oleg Antipov, Maxim Kuznetsov, and Patrice Megret 7.1 Introduction 193 7.2 Theoretical Description of the RIC Effect in Yb-Doped Optical Fibers 194 7.2.1 Introduction: Thermal and Electronic RIC Mechanisms 194 7.2.2 Description of the Spectroscopic Properties of Yb-Doped Optical Fibers 195 7.2.3 Description of the Electronic RIC Mechanism 195 7.2.4 Description of the Thermal RIC Mechanism 200 7.2.5 Comparison of Electronic and Thermal Contributions to the Pump-Induced Phase Shift 201 7.2.6 Phase Shifts in the Case of Periodic Pulse Pumping and in the Presence of Amplified Signal 203 7.2.7 Conclusion 205 7.3 Experimental Studies of the RIC Effect in Yb-Doped Optical Fibers 205 7.3.1 Previous Observations of the RIC Effect in Laser Fibers 205 7.3.2 Methodology of Pump/Signal-Induced RIC Measurements 206 7.3.3 Characterization of RIC in Different Fiber Samples 207 7.3.4 Phase Shifts Induced by Signal Pulses 210 7.3.5 Evaluation of the Polarizability Difference 212 7.3.6 Comparison of the RIC Effects in Aluminum and Phosphate Silicate Fibers 213 7.3.7 Conclusion 215 7.4 All-Fiber Coherent Combining through RIC Effect in Rare Earth-Doped Fibers 215 7.4.1 Coherent Combining of Fiber Lasers: Alternative Techniques 215 7.4.2 Operation Algorithm and Simulated Results 217 7.4.3 Environment Noise in Optical System to be Compensated 222 7.4.4 Combining of Two Er-Doped Amplifiers through the RIC Control in Yb-Doped Fibers 223 7.4.5 Extension Algorithm for Combining of N Amplifiers 224 7.4.6 Conclusion 226 7.5 Conclusions and Recent Progress 226 References 227 8 Coherent Beam Combining of Pulsed Fiber Amplifiers in the Long-Pulse Regime (Nano- to Microseconds) 231 Laurent Lombard, Julien L. Gou€et, Pierre Bourdon, and Guillaume Canat 8.1 Introduction 231 8.2 Beam Combining Techniques 234 8.2.1 Filled and Tiled Apertures 235 8.2.2 Locking Techniques 236 8.2.2.1 Direct Phase Locking Techniques 236 8.2.2.2 Indirect Phase Locking Techniques 237 8.2.3 Requirements of Various Techniques 239 8.2.3.1 Indirect Phase Locking Techniques 239 8.2.3.2 Direct Phase Locking Techniques 240 8.2.4 Case of Pulsed Laser 240 8.3 Amplification of Optical Pulse in Active Fiber 243 8.3.1 Approximations and Validity Domain of the Calculation 243 8.3.2 Pulse Propagation in the Resonant Medium 244 8.3.3 Practical Calculation of the Output Pulse Based on the CW Regime 245 8.3.4 Pulse Shape Distortion 246 8.3.5 Influence of the Amplified Spontaneous Emission 247 8.4 Power Limitations in Pulsed Fiber Amplifiers 248 8.4.1 Physical Principle of the Stimulated Brillouin Scattering 248 8.4.2 SBS Gain 249 8.4.3 SBS Threshold Input Power 250 8.4.4 SBS Reduction 251 8.4.5 Domain of SBS Predominance 251 8.4.6 Physical Principle of the Stimulated Raman Scattering 252 8.4.7 Maximum Peak Power Achievable 253 8.5 Phase Noise and Distortion in Fiber Amplifiers 253 8.5.1 Phase Noise Measurement 253 8.5.2 In-Pulse Phase Shift Measurement 258 8.5.3 In-Pulse Phase Shift Calculation 259 8.5.3.1 Kerr-Induced Phase Shift 260 8.5.3.2 Gain-Induced Phase Shift 262 8.6 Experimental Setup and Results of Coherent Beam Combining of Pulsed Amplifiers Using a Signal Leak between the Pulses 266 8.7 Alternative Techniques for Pulse Energy Scaling 269 8.8 Conclusion 271 References 272 9 Coherent Beam Combining in the Femtosecond Regime 277 Marc Hanna, Dimitrios N. Papadopoulos, Louis Daniault, Frederic Druon, Patrick Georges, and Yoann Zaouter 9.1 Introduction 277 9.2 General Aspects of Coherent Combining over Large Optical Bandwidths 278 9.2.1 Description and Propagation of Femtosecond Pulses 278 9.2.2 Coherent Combining over a Large Bandwidth 280 9.2.3 Influence of Spectral Phase Mismatch on the Combining Efficiency 281 9.2.4 Space–Time Effects 283 9.3 Coherent Combining with Identical Spectra: Power/Energy Scaling 284 9.3.1 Active Techniques 284 9.3.1.1 Experimental Implementations 284 9.3.1.2 Measurement of Spectral Phase Mismatch 287 9.3.2 Passive Coherent Combining Techniques: Path-Sharing Network 290 9.3.2.1 Principle 290 9.3.2.2 Experimental Demonstrations 292 9.4 Other Coherent Combining Concepts 295 9.4.1 Temporal Multiplexing: Divided Pulse Amplification 295 9.4.2 Passive Enhancement Cavities 296 9.4.3 Coherent Combining with Disjoint Spectra: Ultrafast Pulse Synthesis 298 9.5 Conclusion 299 References 300 Part Two: Passive and Self-Organized Phase Locking 303 10 Modal Theory of Coupled Resonators for External Cavity Beam Combining 305 Mercedeh Khajavikhan and James R. Leger 10.1 Introduction 305 10.2 Coherent Beam Combining Requirements 306 10.3 General Mathematical Framework of Passive Laser Resonators 307 10.3.1 Coherent Beam Combining by a Simple Beam Splitter 308 10.3.2 Effect of Wavelength Diversity 311 10.4 Coupled Cavity Architectures Based on Beam Superposition 314 10.4.1 Generalized Michelson Resonators 314 10.4.2 Grating Resonators 318 10.5 Parallel Coupled Cavities Based on Space-Invariant Optical Architectures 321 10.5.1 Space-Invariant Parallel Coupled Resonators with Weakly Coupled Cavities 323 10.5.2 Spatially Filtered Resonators and the Effect of Path Length Phase Errors 325 10.5.3 Talbot Resonators 329 10.6 Parallel Coupled Resonators Based on Space-Variant Optical Architectures: the Self-Fourier Cavity 336 10.7 Conclusion 340 Acknowledgments 341 References 341 11 Self-Organized Fiber Beam Combining 345 Vincent Kermene, Agnes Desfarges-Berthelemot, and Alain Barthelemy 11.1 Introduction 345 11.2 Principles of Passively Combined Fiber Lasers 346 11.2.1 Different Configurations 346 11.2.2 Principles 347 11.3 Phase Coupling Characteristics 350 11.3.1 Power Stability 350 11.3.2 Cophasing Building Dynamics 351 11.3.3 Frequency Tunability 353 11.3.4 Effect of Laser Gain Mismatched on Combining Efficiency 354 11.3.5 Pointing Agility 355 11.3.6 Coherence Properties of Multiple Beams Phase Locked by Mutual Injection Process 356 11.4 Upscaling the Number of Coupled Lasers 360 11.4.1 Phasing Efficiency Evolution 360 11.4.2 Main Influencing Parameters 360 11.5 Passive Combining in Pulsed Regime 362 11.5.1 Q-Switched Regime 362 11.5.2 Mode-Locked Regime 365 11.6 Conclusion 367 References 368 12 Coherent Combining and Phase Locking of Fiber Lasers 371 Moti Fridman, Micha Nixon, Nir Davidson, and Asher A. Friesem 12.1 Introduction 371 12.2 Passive Phase Locking and Coherent Combining of Small Arrays 372 12.2.1 Efficient Coherent Combining of Two Fiber Lasers 372 12.2.2 Compact Coherent Combining of Four Fiber Lasers 375 12.2.3 Efficient Coherent Combining of Four Fiber Lasers Operating at 2 mm 376 12.3 Effects of Amplitude Dynamics, Noise, Longitudinal Modes, and Time-Delayed Coupling 377 12.3.1 Effects of Amplitude Dynamics 377 12.3.2 Effects of Quantum Noise 381 12.3.3 Effects of Many Longitudinal Modes 384 12.3.4 Effects of Time-Delayed Coupling 388 12.4 Upscaling the Number of Phase-Locked Fiber Lasers 391 12.4.1 Simultaneous Spectral and Coherent Combining 391 12.4.2 Phase Locking 25 Fiber Lasers 393 12.5 Conclusion 398 References 398 13 Intracavity Combining of Quantum Cascade Lasers 401 Guillaume Bloom, Christian Larat, Eric Lallier, Mathieu Carras, and Xavier Marcadet 13.1 Introduction 401 13.2 External Cavity Passive Coherent Beam Combining 402 13.2.1 Laser Scheme 403 13.2.2 Modeling of the Coherent Beam Combining in External Cavity 404 13.2.2.1 The Michelson Cavity 404 13.2.2.2 General Case: The N-Arm Cavity 406 13.2.3 Combining Efficiency in Real Experimental Conditions 408 13.2.3.1 Influence of the Number of Arms N 408 13.2.3.2 Influence of the Arm Length Difference DL 409 13.3 Experimental Realization: Five-Arm Cavity with a Dammann Grating 410 13.3.1 Dammann Gratings 410 13.3.2 Quantum Cascade Lasers 413 13.3.3 The Five-Arm External Cavity 414 13.4 Subwavelength Gratings 418 13.4.1 Principle 418 13.4.2 Grating Design and Realization 419 13.4.3 Antireflection Coating Design 422 13.4.4 Calculated Performances 423 13.5 Conclusion 423 References 424 14 Phase-Conjugate Self-Organized Coherent Beam Combination 427 Peter C. Shardlow and Michael J. Damzen 14.1 Introduction 427 14.2 Phase Conjugation 429 14.2.1 Gain Holography 431 14.2.2 Four-Wave Mixing within a Saturable Gain Media 433 14.2.3 Self-Pumped Phase Conjugation 434 14.2.3.1 Seeded Self-Pumped Phase-Conjugate Module 435 14.2.3.2 Self-Starting Self-Adaptive Gain Grating Lasers 437 14.3 PCSOCBC 438 14.3.1 CW Experimental PCSOCBC 439 14.3.2 Understanding Operation of PCSOCBC: Discussion 442 14.3.3 Power Scaling Potential 444 14.3.3.1 Scaling the Number of Modules 445 14.3.3.2 Higher Power Modules 448 14.3.3.3 Pulsed Operation 449 14.4 Conclusions 450 References 451 15 Coherent Beam Combining Using Phase-Controlled Stimulated Brillouin Scattering Phase Conjugate Mirror 455 Hong J. Kong, Sangwoo Park, Seongwoo Cha, Jin W. Yoon, Seong K. Lee, Ondrej Slezak, and Milan Kalal 15.1 Introduction 455 15.2 Principles of SBS-PCM 456 15.3 Reflectivity of an SBS-PCM 457 15.4 Beam Combining Architectures 461 15.5 Phase Controlling Theory 462 15.6 Coherent Beam Combined Laser System with Phase-Stabilized SBS-PCMs 467 15.6.1 Conventional Phase Fluctuation of SBS-PCM 467 15.6.2 Phase Fluctuation without PZT Controlling 468 15.6.3 Phase Fluctuation with PZT Controlling 471 15.7 Conclusions 475 References 475 Index 479

Rezension

“This could be a guide for scientists and engineers who are working on high-power lasers in the fields of industrial, environmental, defense and scientific applications.” (Optics & Photonics News, 28 February 2014)

Autorenportrait

Dr. Arnaud Brignon is Head of the Micro and Nano-Physics Laboratory in Thales Research & Technology, France. He received his Engineering Degree in 1991 from the Institut d?Optique Graduate School, and his PhD in 1996 from the Paris University, France. Arnaud Brignon has authored more than 150 papers (including some 30 invited and tutorials) on laser beam control, two books, and 30 patents. In 1996 he received the Fabry-de-Gramont prize from the French Optical Society, in 2000 the Fresnel prize from the European Physical Society, and in 2001 the Technology Review?s Award from the MIT.