All Optical Wavelength Conversion

Studies of interaction between optical and substance not only have weightilyacademic values but also have widely applied values especially in communica--tion field. In this dissertation physical characteristics of a few all optical wave--length conversion (AOWC)methods are amply researched.In second chapter numerical model of AOWC is established which is base on cross gain modulation in a semiconductor optical amplifier. Nonlinear schrodinger equation is used for studying chirp characteristic in wavelength conversion process. And incidence power, wavelength and bias current affect conversion pulse are simulated. Results as follows: Reducing of SOA chirp in connection with increasing of SOA gain or photon energy; Reducing input light power or increasing length and effective area of active layer, we can reduce the SOA chirp; Code interfering can be reduced when extinction ratio of conversion signal is increased; Enhancing power of prob light, we can improve signal-noise ratio; Wavelength conversion of cross gain modulation of SOA transform along with short wave direction or long wave direction too; When bias current is reduced signal-noise ration will be worsen and code interfering will be augmented.In the next chapter Mach-Zehnder AOWC is researched. Distributed losses of light power in Mach-Zehnder two arms are skillfully dealt by converging method. Intension noise of AOWC is investigated further more relative intension noise. And computer is used for simulating the conversion process. There are five important results to be obtained. The first one is that noise index associate with product of loss coefficient and fiber length. As loss of fiber concentrate in input port, on the contrary, as loss concentrate in output port. The second result is that under NMZI quantum-well qualifications interferometer of nonsensitive phase has about 3dB noise index. The third one is that relative noise factor is increased along with power of signal light, finally it tend to a fix value. Conversion signal can obtain small relative intension noise when signal light and probe light have opposite direction of transmission besides small power of signal and big power of probe. The last one is that conversion signal transform along with short wave direction or long wave direction too but signal of short wave is propitious to transfers more than signal of long wave in fiber. In forth chapter AOWC of four wave mixing (FWM) is detailed investigated with nonlinear high-rank effect of SOA. High frequency unharmonious term is taken in FWM theory. The last collectivity model is set up. Spectrogram, eye-chart and conversion efficiency of conversion pulse are simulated. Big power of coupling light can be obtained when angle frequency of probe light is less than angle frequency of pump light. Base on results of simulation efficiency of conversion is very low about minus 20dB-30dB. Fifthly electric charge distributing is distorted which formed equivalent dipole system when matter is influenced by light field. Found on this physical thought physical characteristics of AOWC about difference frequency and sum frequency are investigated with the method of subsection disposal. Calculation results are in better agreement with experimental datum of literature . Last chapter new all-optical transmultiplexers are researched and feasibilities are demonstrated. And computer is used for designing and simulating the system. Results show transmultiplexers can effective exchange datum between Wavelength Division Multiplexing network and Optical Time Division Multiplexing network . In this thesis the emphasis is theory investigation of AOWC, at the same time, numerical simulation and design are studied too. Holding true areas and Optimization configuration parameters of AOWC are obtained with different methods of wavelength conversion.