Study On The All-optical Logic Gate Of Ultra-fast SOI Micro-waveguide

All-optical logic gates are key components for all-optical communication in future.It is the core device for high-speed optical packet switching,all-optical address recognition,data encoding,all-optical signal processing and optical computing.It has received extensive attention and research.The proposed non-waveguide type all-optical logic gates are large in size and difficult to integrate on-chip.The all-optical logic gate based on waveguide type contains complex active devices and realizes only single logic function.This paper proposes an ultra-fast passive multi-function logic gates(FLOGs)which implement AND,NOT,XOR logic functions by changing the port input and output states on a basic passive Sagnac chip unit.The main research work is summarized as follows:(1)According to the working principle of Sagnac,the all-optical logic gate scheme which can realize the logic functions is analyzed.(2)The realization scheme of all-optical logic gate FLOGs based on micro-waveguide structure is studied,and the FLOGs chip unit is designed.The finite difference time domain algorithm(FDTD)is used to analyze the components of the chip unit including coupler,splitter/combiner and ring structure.The coupler S-shaped curved waveguide and coupling region coupling length are also optimized.The problems that need attention in the preparation of silicon materials are summarized.(3)According to the basic unit of FLOGs,a structural scheme for implementing various logic functions is proposed.The logic functions of FLOGs integrated chip are realized by FDTD and beam propagation method(BPM)simulation.The influence of coupler power ratio on the extinction ratio of the system is analyzed.The solution to the energy residual problem at the reflection end of the system is proposed.The cascading scheme of logic gates(AND gate cascade,AND gate with XOR gate cascade,XOR gate,OR gate)which may be applied to optical neural networks is studied.Studies have shown that the designed cell device has good transmission performance.The working wavelength of the designed coupler is 1550 nm.The power ratio is 0.5,and the additional loss is 0.17 dB.The total length of the polarization splitter/splitter(PBS/PBC)is approximately 10 ?m.The TE mode transmission loss is 0.2 dB.The TM mode transmission loss is 0.36 dB.The FLOGs chip is designed with low power consumption(?W),small size(90 ?m × 20 ?m),short response time(ps),and can implement multiple logic functions(AND,NOT,XOR,XNOR,OR).The FLOGs has a broad application prospect in the future all-optical communication and large-scale integrated optical path.