Study And Optimization Design Of Optical Temporal Differentiator

The development of the silicon-based large-scale integration technology in which electronic and photonic are taken as information carrier, has become an inevitable trend for the development of information technology. As a key technique of all-optical communications,all-optical information processing gains more and more concerns from researchers. Optical Temporal Differentiator(OPD) has been widely used in all-optical information processing.Based on waveguide coupling theory, four programs on realizing Optical Temporal Differentiator are discussed on the principle of Optical Temporal Differentiator in this paper,which are based on the Optical Temporal Differentiators of Micro-Ring Resonator(MRR),Self-Coupled Optical Waveguide(SCOW), parallel micro-ring resonator and series self-coupling micro-ring resonator respectively. Differential characteristics exploration and simulation analysis are conducted for the four programs of Optical Temporal Differentiator in this paper, and the main work is shown as follows.The research significance and development status of Optical Temporal Differentiator are elaborated firstly, with the analysis and summary of several existing implementation programs. The coupling mechanisms of the straight-straight waveguide coupling,straight-bending waveguide coupling and bending-bending waveguide coupling are analyzed further by the application of coupled-mode theory. The change of the transmission power in the coupling process of directional coupler is analyzed by simulation, so as to verify the changing relationship among the coupling coefficient, the waveguide bending radius and the interval of two waveguides in the coupling process of bending waveguide.Secondly, the spectral characteristics of Micro-Ring Resonator and Self-Coupled Optical Waveguide are analyzed, theoretical deduction is conducted for realizing Optical Temporal Differentiator, and the possibilities of realizing differentiation are verified by simulation.Transmission spectra of the two devices are compared with those of the ideal differentiator,which has proved both can achieve the effect of first-order differential in the critical coupling state, and achieve the effect of second-order differential in the over-coupling state. Gaussian pulse input is used to realize the Optical Temporal Differentiators of Micro-Ring Resonator and Self-Coupled Optical Waveguide, and the differential effects of both devices are analyzed through numerical simulation.Finally, based on the coupling theory and working mechanism of Micro-Ring Resonator and Self-Coupled Optical Waveguide, two programs—parallel micro-ring resonator and series self-coupling micro-ring resonator are proposed for realizing the Optical Temporal Differentiator. By using the coupled mode theory, both transmission functions are deduced,and the transmission characteristics of the two are analyzed by simulation. The mechanismsfor realizing Optical Temporal Differentiator are pointed out, and it is proved that parallel micro-ring resonator can achieve 0.46-order and 1.25-order Optical Temporal Differentiator under certain conditions, and series self-coupling micro-ring resonator can achieve 0.7-order and 1.3-order Optical Temporal Differentiator under certain conditions.To realize Optical Temporal Differentiator operation, need to transfer through the filter,so find the filter transfer function is very important. On this basis, the filter transfer function to make use of MATLAB simulation, to find the ideal transmission spectrum, and the time, to simulate the differentiator theory put forward by the analysis of spectrum, for the next deeper research, provide theoretical support.