OPTIMIZATION OF HYPERBOLIC TANGENT APODIZED CHIRPED FIBER BRAGG GRATINGS (CFBG) FOR DISPERSION COMPENSATION IN OPTICAL FIBER COMMUNICATION

Abstract

Chirped fiber Bragg grating is a promising approach for dispersion compensation in optical fiber communication systems, since it’s passive optical component, fiber compatible and has low insertion losses and low costs. Unapodized CFBG is fail to achieve the expected performance due to high ripples in time delay response. Many apodization profiles are suggested to optimize grating performance. Among them, hyperbolic tangent (tanh) apodization profile result in overall superior performance. In this work, the reflection spectrum of CFBG is solved by numerical solution of Reccati differential equation. Results show that, the characteristics of the tanh apodized CFBG can varied systematically according to an angular tanh apodization profile parameter called truncation parameter (atr). By using this parameter the characteristics of the grating is assist in term of limitations of full-wave half maximum reflection bandwidth and minimizing average time-delay ripples for different truncation parameter values. Results show that for a given chirped parameter value CFBG approach optimal performance at truncation parameter of 4. In optical communication bandwidth of 0.5nm CFBG can compensate linear dispersion of 100 km of standard optical fiber length, the required grating length is 10 cm. According to these results, the truncation parameter must be chosen carefully in performance optimization of the hyperbolic tanh apodized chirped fiber Bragg grating.