Research On Optical Phase Arithmetic Devices Using Four Wave Mixing

High-speed and large-capacity all-optical signal processing can be achieved in the future with the optical logic arithmetic device.Such devices can capable of overcoming the speed limitation of electronics,and help reduce data transmission delays.The optical logic phase arithmetic unit can be realized by the Four-Wave Mixing?FWM?nonlinear effect in the highly nonlinear fiber.Based on the phase relationship between the idler and the input signals in the Phase-Insensitive Amplifier?PIA?mode of the FWM process,the all-optical logic operation of high-order phase modulation format signals is implemented.The innovation of this thesis is reflected in the following three aspects:?1?Using the limit analysis method,the phase relationship of the FWM-PIA addition and subtraction hybrid arithmetic unit is proved,which provides a theoretical basis for the design of phase arithmetic device;?2?Single-channel and three-channel phase arithmetic device are designed,and their amplitude and phase noise transfer performance are compared;?3?The performance of the inter-mode four wave mixing?IM-FWM?optical phase arithmetic unit in few-mode fiber?FMF?is analyzed.When the symbol-error Rate?SER?of the error-free coding is less than 10^-3,The signal-to-noise ratio?SNR?of the input guided wave is required to be greater than 25 dB and the Error Vector Magnitude?EVM?is less than 13%.The specific content of this thesis is as follows:1.The universal analytic expression for the amplitude and phase of the idler in degenerate and non-degenerate FWM process under pump depletion is derived.By using equivalent infinitesimal to calculate the limit of phase insensitive amplification,the initial phase relationship between the idler and the input guided wave for phase-independent amplification is found,which is crucially important for explaining the operating principles of the FWM-based adder and subtracter.Taking quadrature phase-shift keying?QPSK?signal as an example,this thesis present the configuration of non-degenerate FWM-based hybrid arithmetic device and focus on the noise transfer characteristic dependent on fiber length,input wavelength and optical power.Calculation results show that,this kind of arithmetic device has a noise figure of about 1.1dB and the input SNR of more than 24dB is necessary for the symbol error rate of<10^-3 without forward error correction.2.This study proposes a hybrid arithmetic devices of three-channel optical phase for optical computing?A+B-C,A+C-B,and B+C-A?that is designed according to the phase-insensitive amplification principle of FWM in fibers.The nonlinear coupled-mode equations for the cascade FWM are derived.Results reveal that between each output idler and input signal have a certain phase relation,which provides the theoretical basis for phase compensation.Moreover,parallel hybrid arithmetic devices have amplitude noise index and phase noise transfer coefficient in terms of EVM of 0.9 dB and 1.67,respectively.For a QPSK signal,when the SNR is>24 dB and the EVM is<12%,the SER of error-free coding is<10^-3.Three-and single-channel arithmetic devices exhibit the same phase noise transfer characteristics,however,the three-channel arithmetic device exhibits lower phase noise of 0.2 dB and larger power transfer efficiency that is more than twice that of the single-channel arithmetic device.3.A phase arithmetic device in Space Division Multiplexing?SDM?system is designed by phase intermodulation principle of Intermode Four-Wave Mixing?IM-FWM?process in FMF.By solving the analytical solution of the IM-FWM coupled mode equation in the few-mode fiber,the certain phase relation between the output idler and input signal is proved again,which provides the theoretical basis for phase compensation in the few-mode fiber.Calculation results show that,The amplitude noise index of the non-degenerate IM-FWM hybrid operation is about 1.4 dB,and the phase noise transfer coefficient in terms of EVM is 1.69.For QPSK signal,In order to ensure the SER of phase arithmetic device error-free coding is<10^-3,the SNR should be>25 dB and the EVM should be<13%.