All-optical Clock Recovery And UWB Technology Based On Optical Fiber Nonlinearity

The target of future optical network development is to increase the network capacityand bit rate of signal channel. In future all-optical network, signal processing at switchingnodes will be implemented in optical domain without additional O-E-O conversion, whichincreases speed and decreases power consumption. All-optical clock recovery (AOCR) as akey part of all-optical processing technology is always used for3R regeneration at theswitching nodes and for signal detetion at the receiver side in optical network. Moreover, itcan be ultilized for network health monitoring.On the other hand, in order to transimit ultra-wideband (UWB) signal with largebandwidth and low power density to long distance, UWB-over-Fiber (UWBoF) technologywhich combines two world (wire and wireless) appeared naturally and attracted a great dealof attention.This thesis detailly analyzed the fiber-nonlinearity-based AOCR subsystem based onboth theory as well as experiment. Also, fiber-nonlinearity structure was introduced toUWBoF system for UWB signal generation, modulation, transimission, and multicasting.The main contents of this thesis are as follows:(1) Based on the principle of nonlinear polarization rotation (NPR) in highly nonlinearfiber (HNLF) and actively harmonic mode-locking theory, we demonstrate all-opticalactively harmonic mode-locked laser operation at40GHz and80GHz.(2) Based on the actively harmonic mode-locked laser incorporating NPR, an AOCRsubsystem that can operate at40Gb/s and80Gb/s is demonstrated. We also analyze the40Gb/s recovered clock properties as a function of the input signal parameters.(3) The gain properties of different parametric amplifiers are analized with differentinput in detail by numerical solution coupling wave functions. Based on the simulationresults mentioned above,40Gb/s AOCR is realized.(4) By exploiting NOLM as the all-optical mode-locking element, repetition rate at10GHz and20GHz mode-locked pulse can be generated by setting propriate bias votage tothe Mach-Zehnder modulator which is driven by10GHz electrical signal.(5) The operation speed of the AOCR subsystem based on NOLM is promoted to40 Gb/s. Moreover, we analyze the recovered clock properties as a function of the input signalaverage power, extinction ratio, DGD and SOA current.(6) We compare three different fiber-nonliear-based AOCR approaches mentionedabove comprehensively. According to the analysis, NPR-based subsystem is the best AOCRsubsystem among the three mentioned in this thesis.(7) An approach to convert (non-return-to-zero) NRZ signal to self-clockingManchester code at20Gb/s based on two-direction-pumped NOLM is demonstratedexperiementally.(8) By digging the principle of the NOLM in-depth, we demonstrate, for the first time,an UWBoF system that using the nonlinear power transmission region of the NOLM toproduce UWB signal. UWB doublet pulses with reversed polarity have been generatedexperimentally. Those pulses are then on-off-keying (OOK) modulated and transmittedover10km fiber link. Error-free performance can be achived at the receiver side.(9) By improving the structure mentioned above, and using the wide-bandwidth andlow-cross-talk characteristics of Kerr effect, an UWBoF system with multicasting ability isproposed. Five channels UWB signals with different polarity and shape are generatedexperimentally.