Fiber Optic Measurement Techniques

Cover Page
......Page 1
Copyright......Page 2
Dedication......Page 3
Preface......Page 4
Acknowledgements......Page 5
About the Author......Page 7
Constants......Page 8
Fundamentals of Optical Devices......Page 9
Introduction......Page 10
Laser Diodes and LEDs......Page 12
Pn Junction and Energy Diagram......Page 13
Direct and Indirect Semiconductors......Page 14
Carrier Confinement......Page 15
Spontaneous Emission and Stimulated Emission......Page 16
Light-Emitting Diodes (LEDs)......Page 17
PI Curve......Page 18
Modulation Dynamics......Page 20
Laser Diodes (LDs)......Page 21
Rate Equations......Page 24
Threshold Current Density......Page 26
PJ Relationship About Threshold......Page 27
Mode Suppression Ratio (MSR)......Page 28
Turn-on Delay......Page 30
Small-Signal Modulation Response......Page 31
Phase Noise......Page 33
Single-Frequency Semiconductor Lasers......Page 34
DFB Laser Diode......Page 35
External Cavity Laser Diode......Page 36
Pn-Junction Photodiodes......Page 40
Responsivity and Bandwidth......Page 42
Electrical Characteristics of a Photodiode......Page 44
Photodetector Noise and SNR......Page 45
Noise-Equivalent Power (NEP)......Page 48
Avalanche Photodiodes (APDs)......Page 49
Reflection and Refraction......Page 52
Fresnel Reflection Coefficients......Page 53
Normal Incidence......Page 55
Optical Field Phase Shift Between the Incident and the Reflected Beams......Page 56
Propagation Modes in Optical Fibers......Page 57
Geometric Optics Analysis......Page 59
Mode Analysis Using Electromagnetic Field Theory......Page 62
Numerical Aperture......Page 66
Optical Fiber Attenuation......Page 70
Phase Velocity and Group Velocity......Page 75
Group Velocity Dispersion......Page 77
Sources of Chromatic Dispersion......Page 78
Modal Dispersion......Page 81
Polarization Mode Dispersion (PMD)......Page 82
Stimulated Brillouin Scattering......Page 85
Stimulated Raman Scattering......Page 86
Kerr Effect Nonlinearity and Nonlinear Schrödinger Equation......Page 87
Optical Amplifiers......Page 93
Optical Gain, Gain Bandwidth, and Saturation......Page 94
Steady-State Analysis......Page 97
Gain Dynamics of OSA......Page 99
Optical Wavelength Conversion Using Cross-Gain Saturation......Page 103
Wavelength Conversion Using FWM in SOA......Page 104
Optical Phase Modulation in an SOA......Page 107
Erbium-Doped Fiber Amplifiers (EDFAs)......Page 108
Absorption and Emission Cross-Sections......Page 110
Rate Equations......Page 112
Forward Pumping and Backward Pumping......Page 118
EDFAs with AGC and APC......Page 119
EDFA Gain Flattening......Page 122
External Electro-Optic Modulator......Page 123
Basic Operation Principle of Electro-Optic Modulators......Page 124
Frequency Doubling and Duo-Binary Modulation......Page 129
Optical Single-Side Modulation......Page 131
Optical Modulators Using Electro-Absorption Effect......Page 133
References
......Page 135
Basic Instrumentation for Optical Measurement......Page 137
Introduction......Page 138
General Specifications......Page 139
Fundamentals of Diffraction Gratings......Page 142
Measure the Diffraction Angle Spreading Whenthe Input Only has a Single Frequency......Page 144
Sweep the Signal Wavelength While Measuringthe Output at a Fixed Diffraction Angle......Page 145
Basic OSA Configurations......Page 146
Basic FPI Configuration and Transfer Function......Page 154
Free Spectral Range (FSR)......Page 158
Contrast......Page 159
Scanning FPI Spectrum Analyzer......Page 161
Scanning FPI Basic Optical Configurations......Page 165
Optical Spectrum Analyzer Using the Combination of Grating and FPI......Page 167
Mach-Zehnder Interferometers......Page 168
Michelson Interferometers......Page 176
Operating Principle of a Michelson Interferometer......Page 177
Measurement and Characterization of Michelson Interferometers......Page 180
Techniques to Increase Frequency Selectivity......Page 182
Optical Wavelength Meter......Page 187
Operating Principle of a Wavelength Meter Based on Michelson Interferometer......Page 188
Wavelength Coverage......Page 191
Spectral Resolution......Page 192
Wavelength Calibration......Page 193
Wavelength Meter Based on Fizeau Wedge Interferometer......Page 194
General Description of Lightwave Polarization......Page 196
The Stokes Parameters and the Poincare Sphere......Page 198
Optical Polarimeters......Page 201
Operating Principle......Page 204
Heterodyne and Homodyne Detection......Page 207
Signal-to-Noise-Ratio in Coherent Detection Receivers......Page 209
Balanced Coherent Detection and Polarization Diversity......Page 210
Phase Diversity in Coherent Homodyne Detection......Page 212
Coherent OSA Based on Swept Frequency Laser......Page 215
Waveform Measurement......Page 219
Oscilloscope Operating Principle......Page 220
Digital Sampling Oscilloscopes......Page 224
High-Speed Sampling of Optical Signal......Page 227
Nonlinear Optical Sampling......Page 228
Linear Optical Sampling......Page 229
High-Speed Electric ADC Using Optical Techniques......Page 231
Optical Low-Coherence Reflectometry......Page 240
Fourier-Domain Reflectometry......Page 248
S-Parameters and RF Network Analyzer......Page 254
Optical Network Analyzers......Page 257
Scalar Optical Network Analyzer......Page 258
Vector Optical Network Analyzer......Page 259
References......Page 264
Characterization of Optical Devices......Page 267
Characterization of RIN and Linewidth of Semiconductor Lasers......Page 268
Measurement of Relative Intensity Noise (RIN)......Page 269
Measurement of Laser Phase Noise and Linewidth......Page 274
Coherent Detection......Page 277
Self-homodyne detection......Page 280
Measurement of Electro-Optic Modulation Response......Page 284
Frequency-Domain Characterization......Page 285
Time-Domain Characterization......Page 289
Measurement of Frequency Chirp......Page 290
Modulation Spectral Measurement......Page 291
Measurement Utilizing Fiber Dispersion......Page 293
Time-Domain Measurement of Modulation-Induced Chirp......Page 300
Wideband Characterization of an Optical Receiver......Page 304
Characterization of Photodetector Responsivity and Linearity......Page 305
Frequency Domain Characterization of Photodetector Response......Page 307
Photodetector Bandwidth Characterization Using Source Spontaneous-Spontaneous Beat Noise......Page 309
Photodetector Characterization Using Short Optical Pulses......Page 312
Measurement of Amplifier Optical Gain......Page 314
Dynamic Gain Tilt......Page 319
Optical Amplifier Noise......Page 322
Optical Domain Characterization of ASE Noise......Page 324
Impact of ASE Noise in Electrical Domain......Page 326
Signal-Spontaneous Emission Beat Noise......Page 327
Spontaneous-Spontaneous Beat Noise Spectral Density......Page 329
Noise Figure Definition......Page 331
Electrical Domain Characterization of a Noise Figure......Page 333
Time-Domain Characteristics of EDFA......Page 335
Characterization of Passive Optical Components......Page 337
Fiber-Optic Couplers......Page 338
Fiber Bragg Grating Filters......Page 343
Thin Film-Based Interference Filters......Page 348
Arrayed Waveguide Gratings......Page 351
Characterization of Optical Filter Transfer Functions......Page 353
Modulation Phase-Shift Technique......Page 354
Interferometer Technique......Page 358
Optical Isolators......Page 361
Optical Circulators......Page 364
Reference......Page 369
Optical Fiber Measurement......Page 372
Introduction......Page 373
Standard Optical Fibers for Transmission......Page 374
Specialty Optical Fibers......Page 377
Measurement of Fiber Mode-Field Distribution......Page 381
Near-Field, Far-Field, and Mode-Field Diameter......Page 382
Far-Field Measurement Techniques......Page 385
Near-Field Measurement Techniques......Page 387
Cutback Technique......Page 389
Optical Time-Domain Reflectometers......Page 391
Improvement Considerations of OTDR......Page 398
Fiber Dispersion Measurements......Page 401
Intermodal Dispersion and Its Measurement......Page 402
Pulse Distortion Method......Page 403
Frequency Domain Measurement......Page 405
Modulation Phase Shift Method......Page 407
Baseband AM Response Method......Page 410
Interferometric Method......Page 412
Representation of Fiber Birefringence and PMD Parameter......Page 416
Pulse Delay Method......Page 420
The Interferometric Method......Page 422
Poincare Arc Method......Page 425
Fixed Analyzer Method......Page 427
The Jones Matrix Method......Page 431
The Mueller Matrix Method......Page 438
Determination of Polarization-Dependent Loss......Page 445
PMD Sources and Emulators......Page 449
Measurement of Fiber Nonlinearity......Page 453
Measurement of Stimulated Brillouin Scattering Coefficient......Page 454
Measurement of the Stimulated Raman Scattering Coefficient......Page 460
Measurement of Kerr effect nonlinearity......Page 466
Nonlinear Index Measurement Using SPM......Page 467
Nonlinear Index Measurement Using FWM......Page 470
Nonlinear Index Measurement Using Cross-Phase Modulation......Page 475
Nonlinear Index Measurement Using Modulation Instability......Page 480
Optical System Performance Measurements......Page 487
Introduction......Page 488
Overview of Fiber-Optic Transmission Systems......Page 489
Optical System Performance Considerations......Page 490
Receiver BER and Q......Page 492
System Q Estimation Based on Eye Diagram Parameterization......Page 500
Bit Error Rate Testing......Page 505
Pattern Generator......Page 507
Error Detection......Page 510
Receiver Sensitivity Measurement and OSNR Tolerance......Page 514
Receiver Sensitivity and Power Margin......Page 515
OSNR Margin and Required OSNR (R-OSNR)......Page 520
BER vs. Decision Threshold Measurement......Page 527
Waveform Distortion Measurements......Page 530
Basic Jitter Parameters and Definitions......Page 533
Jitter Measurement Based on Sampling Oscilloscope......Page 538
Jitter Measurement Based on a Phase Detector......Page 540
Jitter Measurement Based on a BER-T Scan......Page 541
In Situ Monitoring of Chromatic Dispersion......Page 543
Basic Operating Principle......Page 547
PMD Monitoring Using Coherent Detection......Page 549
Difference Between Fiber DGD and the DGD Experienced by an Optical Signal......Page 553
In Situ PDL Monitoring......Page 557
XPM-Induced Intensity Modulation in IMDD Optical Systems......Page 562
XPM-Induced Phase Modulation......Page 578
FWM-Induced Crosstalk in IMDD Optical Systems......Page 581
Characterization of Raman Crosstalk with Wide Channel Separation......Page 587
Modulation-Instability and Transfer Matrix Formulation......Page 596
Power Spectrum of The Optical Field......Page 599
Noise Description at a Direct-detection Optical Receiver......Page 601
Effect of Dispersion Compensation......Page 604
Impact of Modulation Instability in Amplified Multispan Fiber Systems......Page 606
Characterization of Modulation Instability in Fiber-Optic Systems......Page 607
Optical System Performance Evaluation Based on Required OSNR......Page 612
Measurement of R-SNR Due to Chromatic Dispersion......Page 613
Measurement of R-SNR Due to Fiber Nonlinearity......Page 616
Measurement of R-OSNR Due to Optical Filter Misalignment......Page 621
Fiber-Optic Recirculating Loop......Page 622
Operation Principle of a Recirculating Loop......Page 623
Measurement Procedure and Time Control......Page 624
Optical Gain Adjustment in the Loop......Page 628
Reference......Page 634