1 Introduction ................................................. 1
1.1 Optical communication systems ........................... 2
1.2 Fiber impairments and equalizers ........................ 4
1.3 Outline of the thesis ................................... 6
2 Basics ....................................................... 7
2.1 Linear fiber transfer function .......................... 7
2.2 Fiber nonlinearities ................................... 11
2.3 Compensation of chromatic dispersion ................... 15
2.4 Delay Line Filters ..................................... 18
2.4.1 Mathematical Description ........................ 18
2.4.2 Realization options ............................. 19
2.4.3 Realization in Optics ........................... 21
3 Filter synthesis ............................................ 27
3.1 Mathematical description and normalization ............. 28
3.2 Performance limits ..................................... 33
3.3 Iterative methods ...................................... 36
3.3.1 Particle swarm optimization ..................... 36
3.3.2 Other iterative methods ......................... 41
3.3.3 Conclusion ...................................... 44
3.4 Analytical methods for special cases ................... 44
3.4.1 Second order dispersion compensating filter ..... 44
3.4.2 Simplified higher order filter for dispersion
compensation .................................... 49
3.4.3 Dispersion slope compensating filter ............ 52
4 Dispersion Monitoring ....................................... 61
4.1 Vestigial sideband filtering ........................... 61
4.1.1 Proof-of-concept ................................ 63
4.1.2 Electronic estimation ........................... 64
4.1.3 Conclusion ...................................... 71
4.2 Nonlinear Detection .................................... 72
4.2.1 Theoretical investigation ....................... 72
4.2.2 Experiments ..................................... 80
5 Control algorithms for filter adaptation .................... 91
5.1 Control strategies ..................................... 91
5.1.1 Iterative setting ............................... 93
5.1.2 Deterministic setting ........................... 94
5.1.3 Results ......................................... 95
5.2 Example implementations ................................ 98
5.2.1 Wavelength centering ............................ 98
5.2.2 Autonomous dispersion compensation ............. 100
6 Fiber optic dispersion compensator and monitor ............. 105
6.1 Filter elements ....................................... 105
6.1.1 Fiber optic couplers ........................... 105
6.1.2 Fiber delay lines .............................. 106
6.1.3 Phase shifters ................................. 106
6.2 Dispersion compensator and Monitor .................... 107
6.2.1 Analysis and Optimization ...................... 108
6.2.2 Realization .................................... 113
6.3 Device characterization ............................... 114
6.3.1 Single channel characterization ................ 116
6.3.2 Multi channel characterization ................. 118
6.4 System characterization ............................... 118
6.4.1 Multi channel measurements ..................... 121
6.4.2 Single channel measurements .................... 126
6.5 Dispersion slope compensator .......................... 128
7 Future directions .......................................... 133
8 Conclusion ................................................. 135
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