Key Technologies Of All-optical Signal Processing Based On Nonlinearities In SOA

This dissertation mainly focuses on the subject of all-optical signal processing technologies based on the nonlinearities in semiconductor optical amplifiers (SOAs), including all-optical wavelength conversion, all-optical demultiplexing, all-optical NRZ-to-RZ format conversion and all-optcial AND logic gate. Several new schemes are presented about the four kinds of super-high speed all-optical network technologies for the first time or independently. Numerical analyses based on the improved theoretical model and experimental analyses are conducted. In addition, the adaptive feedback control of the input polarization state used for controling the polarization state of the superposed beams in coherent optical fiber communications and optical fiber sensor devices is discussed in detail.1. Characteristics and theoretical model of nonlinear polarization rotation in SOATwo carrier temperature equations are introduced to substitute two energy density equations to reduce the complexity of calculation compared to the previous model. Based on the improved model, numerical analyses are conducted about polarized characteristics of gain and phase shift in SOA. The simulated results are good agreement with the experimental results.2. All-optical wavelength conversion and demultiplexing based on nonlinear polarization rotation in SOATwo kinds of wavelength conversion schemes based on nonlinear polarization rotation in SOA are analyzed by simulation based on the improved model and experiment at 20Gbit/s in detail for the first time, which are the wavelength conversion scheme only based on nonlinear polarization rotation in SOA and the wavelength conversion scheme based on nonlinear polarization rotation in SOA assisted with red-shifted filtering. The simulated results are good agreement with the experimental results. The results show that the performance of the wavelength conversion scheme based on nonlinear polarization rotation in SOA assisted with red-shifted filtering is higher than that of the wavelength conversion scheme only based on nonlinear polarization rotation in SOA.Three kinds of all-optical wavelength conversion schemes based on nonlinear polarization rotation in SOA are achieved at the rate of 640Gbit/s for the first time, which are all-optical wavelength conversion scheme only based on nonlinear polarization rotation in SOA, all-optical wavelength conversion scheme based on nonlinear polarization rotation in SOA assisted with red-shifted filtering and all-optical wavelength conversion scheme based on nonlinear polarization rotation in SOA assisted with blue-shifted filtering. Three kinds of 640Gbit/s all-optical wavelength conversion schemes are compared. The effects of some key parameters on the performance of the three kinds of wavelength conversion schemes are investigated. The results show that the performance of the all-optical wavelength conversion scheme based on nonlinear polarization rotation in SOA assisted with blue-shifted filtering is highest among them at the same conditions.640Gbit/s to 80Gbit/s all-optical demultiplexing scheme based on nonlinear polarization rotation in SOA is invesitaged by numerical simulation for the first time, which include the characteristics of switching window induced by clock pulses and the effects of some key parameters on the performance of the demultiplexing scheme, shch as the injected power of clock signal, the injected current of SOA, the pulse width of the injected clock pulse and the polarization angle of the injected clock signal.3. All-optical NRZ-to-RZ format conversion and all-optical AND logic gate based on the nonlinearities of SOATwo novel schemes are independently proposed to achieve NRZ-to-RZ format conversion by exploiting nonlinearities in SOA assisted with blue-shifted filtering, which are the NRZ-to-RZ format conversion based on nonlinear polarization rotation in SOA assisted with blue-shifted filtering (NPR-BF) and the NRZ-to-RZ format conversion based on cross-phase modulation in SOA assisted with blue-shifted filtering (XPM-BF). The basic structures and principles of the two kinds of NRZ-to-RZ format conversions are presented and the two kinds of NRZ-to-RZ format conversions are also achieved by experiment. The experimental results show that the performance of NPR-BF scheme is higher than that of XPM-BF scheme at the same conditions. The two kinds of NRZ-to-RZ format conversions are also achieved by simulation besed on the improved model of nonlinear polarization rotation in SOA.A novel scheme is independently proposed to achieve all-optical AND logic gate by exploiting nonlinearities in SOA. The basic structure and principle of all-optical AND logic gate is presented and is also achieved by simulation at the rate of 40Gbit/s. Through numerical analyses and discussions, it can be seen that the performance of the proposed scheme is higher than that of Terahertz optical asymmetric demultiplexer scheme in terms of the output extinction ratio (ER) and the output pattern effect at the same conditions. Furthermore, the proposed scheme is potentially capable of AND operation speed to 100Gbit/s.4. Technology of adaptive feedback control of the input polarization stateNovel theoretical analyses on the adaptive feedback control of the input polarization state are presented. The model of the adaptive feedback control is established by the theoretical analyses. The possible steady points of the control system are also presented. The simulated results illustrate that the best performance can be obtained when the five power of visibility is considered as feedback signal.