Single Frequency Semiconductor Lasers (eBook)

The authors work at the Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences. They have been engaged in the field of semiconductor lasers, optical communications and optical fiber sensors for many years. Their work focuses on applications of single frequency semiconductor laser, such as laser cooling, highly precise interferometers and coherent optical communications in recent years. 

Preface 6
Contents 9
1 Introduction 14
1.1 Historical Review of Semiconductor Laser 14
1.2 Single Frequency Semiconductor Lasers and Their Applications 16
References 20
2 Fundamentals of Semiconductor Lasers 22
2.1 Stimulated Emission in Semiconductor 22
2.2 P-N Junction, Heterostructure, and Quantum Well 26
2.2.1 Carrier Injection with P-N Junction 26
2.2.2 Heterostructure and Quantum Well 27
2.3 Cavity Structure and Transverse Modes 29
2.3.1 Basic Structure and Transverse Modes 29
2.3.2 Index Guiding and Gain Guiding 32
2.3.3 Laser Array and Modules 33
2.4 Rate Equation and Output Characteristics 34
2.4.1 Lasing Condition 34
2.4.2 Rate Equations 36
2.4.3 Light–Current Characteristics 37
2.5 Longitudinal Modes and Tunability 40
2.5.1 Longitudinal Mode Characteristics 40
2.5.2 Tunability of Semiconductor Lasers 42
2.6 Transient and Modulation Characteristics 43
2.6.1 Modulation of Output Power 43
2.6.2 Relaxation Oscillation 46
2.6.3 Wavelength Modulation 47
2.7 Thermal Performances 48
2.7.1 Dependence of Threshold and Output Power on Temperature 48
2.7.2 Dependence of Laser Spectrum on Temperature 49
2.7.3 Junction Temperature and Thermal Resistant 50
References 52
3 Noises and Stability of Semiconductor Lasers 53
3.1 Characteristics and Inherent Relations of Laser Noises 53
3.1.1 Mathematical Description of Stochastic Variables 53
3.1.2 Phase Noise and Frequency Noise 55
3.1.3 Intensity Noise 57
3.2 Linewidth and Line Shape of Semiconductor Lasers 58
3.2.1 Linewidth of Semiconductor Lasers 58
3.2.2 Effect of Photon-Carrier Coupling on Line Shape and Noise 61
3.2.3 Measurement of Linewidth 62
3.3 Noises of Semiconductor Laser 66
3.3.1 Characteristics of Frequency Noise in Low Frequency Band 67
3.3.2 Measurement of Laser Noises 70
3.3.3 Intensity Noise and Its Suppression 77
3.4 Frequency Stability and Allan Variance 79
3.4.1 Characterization of Frequency Stability 79
3.4.2 Measurement of Allan Variance 82
3.5 Other Effects and Manifestations of Laser Noises 83
3.5.1 Chaos of Semiconductor Lasers 84
3.5.2 Jitter of Laser Pulses, Mode Partition Noise, and Speckles 87
3.5.3 Noise and Instability Related to Internal Defects 88
References 89
4 Monolithically Integrated Semiconductor Lasers 92
4.1 Distributed Feedback Semiconductor Laser 92
4.1.1 Coupled Mode Theory of DFB Laser 92
4.1.2 Characteristics of DFB Lasers 98
4.1.3 Structures and Fabrication of DFB Laser 103
4.2 Distributed Bragg Reflector Semiconductor Laser 105
4.2.1 Structures and Principle of DBR Laser 105
4.2.2 Reflection Spectrum of Passive Waveguide Grating 106
4.2.3 Characteristics of DBR Lasers 108
4.3 Vertical Cavity Surface Emitting Laser 111
4.3.1 Principles of VCSEL 111
4.3.2 Design and Fabrication of VCSEL 113
4.3.3 Characteristics of VCSEL 118
References 123
5 External Cavity Semiconductor Lasers 127
5.1 General Characteristics and Theory of External Cavity Diode Lasers 127
5.1.1 Basic Model of ECDL 127
5.1.2 Linewidth Reduction of ECDL with Weak Feedback 130
5.1.3 Characteristics of ECDL with Frequency Selective Feedback 132
5.1.4 Injection Locking of Semiconductor Lasers 137
5.2 Planar Grating External Cavity Diode Laser 140
5.2.1 Basic Characteristics of Planar Grating 140
5.2.2 Littrow and Littman ECDL 142
5.2.3 Technical Issues of Grating ECDL 147
5.2.4 Various Cavity Structures and Tuning Schemes 150
5.3 Bragg Grating External Cavity Diode Laser 152
5.3.1 Fiber Bragg Grating ECDL 152
5.3.2 Waveguide Bragg Gating ECDL 159
5.3.3 Volume Bragg Grating ECDL 161
5.4 Diode Laser with Cavity Feedback 166
5.4.1 Feedback from Fabry-Perot Cavity 166
5.4.2 Feedback from Ring Cavity 170
References 173
6 Frequency Stabilization of Semiconductor Lasers 177
6.1 Introduction to Saturated Absorption Spectroscopy 177
6.1.1 Classical Theory of Absorption Spectrum 178
6.1.2 Doppler Broadening and Saturated Absorption Spectroscopy 180
6.2 Frequency Stabilization by Modulation Spectroscopy 185
6.2.1 Spectrum of Frequency Modulated Optical Signals 185
6.2.2 Frequency Stabilization with Modulation 188
6.2.3 Residual Amplitude Modulation and Its Removal 191
6.3 Modulation-Free Frequency Stabilization 194
6.3.1 Frequency Stabilization by Polarization Spectroscopy 194
6.3.2 Frequency Stabilization with Sagnac Interferometer 196
6.3.3 Frequency Stabilization by Magnetic Dichroism 199
6.3.4 Frequency Stabilization by Optical Negative Feedback 201
6.4 Pound–Drever–Hall (PDH) Frequency Stabilization 203
6.4.1 Basic Principle of PDH Method 203
6.4.2 Technical Issues of PDH Frequency Stabilized Laser 207
6.4.3 Different Schemes Based on Resonant Cavities 209
6.5 Noise Reduction by Self-mixing Interference 210
References 211
7 Frequency Sweeping of Semiconductor Lasers 215
7.1 Applications of Frequency-Swept Laser 215
7.2 Frequency Sweeping by LD Current Modulation 218
7.2.1 LD Current Tuning and Its Linearization 218
7.2.2 Linewidth Reduction of Frequency-Swept Lasers 222
7.3 Frequency Sweeping with Intra-cavity Tuning Devices 224
7.3.1 Electro-optic Materials and Devices 224
7.3.2 Frequency Sweeping with Intra-cavity Modulator 229
7.3.3 Frequency Sweeping by Intra-cavity Beam Deflection 230
7.4 Frequency Sweeping with Extra-Cavity Modulators 234
7.4.1 Frequency Shifting and Sweeping with Acousto-Optic Modulators 234
7.4.2 Frequency Sweeping with Electro-optic Modulators 237
References 241
8 Optical Phase Locked Loop and Frequency Transfer 245
8.1 Optical Phase Locked Loop 245
8.1.1 Principles of OPLL 245
8.1.2 Injection Locking of Semiconductor Lasers 248
8.2 Applications of OPLL in Laser Frequency Transfer 249
8.2.1 Coherent Optical Communication 249
8.2.2 Transportation of Time and Frequency Signals 254
8.2.3 Microwave Photonics and Radio Over Fiber 256
8.2.4 Researches on Atomic Physics 259
8.3 Optical Frequency Comb and Its Characteristics 262
8.3.1 Principle of Mode-Locked Laser 262
8.3.2 Application of Four Wave Mixing in Frequency Trimming 264
8.3.3 Control of Carrier-Envelope Phase 265
8.4 Applications of Optical Frequency Comb in Laser Frequency Transfer 268
8.4.1 Optical Frequency Locking and Frequency Synthesizer 268
8.4.2 High Precision Optical Frequency Sweeping 270
References 272
9 Applications of Single-Frequency Semiconductor Lasers 277
9.1 Applications in Laser Cooling and Related Technologies 277
9.1.1 Time Standard and Atomic Clock 277
9.1.2 Laser Cooling of Atoms and Cold Atomic Clock 279
9.1.3 Data for Atomic Physics and Related Spectroscopy 284
9.2 Applications in Optical Communications 288
9.2.1 A Brief Review of Optical Fiber Communications 288
9.2.2 Lasers for Coherent Optical Communications 289
9.2.3 Microwave Photonics and ROF 292
9.2.4 Inter-satellite Optical Communications 293
9.3 Applications in Metrology and Sensors 295
9.3.1 High Precision Interferometry 295
9.3.2 Distributed Optical Fiber Sensors 297
9.3.3 Laser Spectroscopy 303
9.4 Applications in Lidar 306
9.4.1 Basic Concept of Lidar 306
9.4.2 Brief Introduction to Synthetic Aperture Lidar 308
References 309
10 Erratum to: Single Frequency Semiconductor Lasers 313
Erratum to:& #6
Index 314