NUMERICAL SIMULATION FOR HIGH- SPEED ALL- OPTICAL BOOLEAN GATES

Abstract

In this paper few high speed (i.e. as high as 80 GB/s) all-optical logic gates has been studied.These logic gates include a ( 80Gb/s XOR ) gate using semiconductor optical amplifier (SOA)based Mach-Zehnder interferometer incorporated with a delayed interferometer (DI), Theperformance of XOR operation has been investigated using numerical simulations. The quality ofthe XOR result is improved using a (DI) delayed interferometer after the Mach-Zehnderinterferometer. . A (80Gb/s XNOR) gate using four wave mixing (FWM) in highly nonlinearfibers (HNLF) have been studied also, the four wave mixing process is a very fast process infibers ,the nonlinear Schrödinger equation that describes (FWM) process in fiber is solvednumerically using the split-step Fourier transform method ,this scheme is capable of operating ata data rate as high as 250Gb/s ,finally A(40Gb/s) NOR gate operation has been analyzed by anumerical solution of the SOA rate equations. To investigate the quality of NOR operation bysimulation, Q factor of the NOR output signal has been calculated. Q factor gives the informationof the optical signal to noise ratio in digital transmission .All numerical simulation programsperformed through Matt-Lab 7.0 prgram.