Calculation of the Transmission Spectrum of Long-Period Fiber Grating Based on the Mode Field Analysis Method

Abstract

By using the coupled mode theory, the vector expressions of the core and the cladding electromagnetic field components of long-period fiber grating are analyzed. After the effective refractive indexes and the coupling constants of the core and cladding mode are solved, the transmission spectrum of the long-period fiber grating is obtained through solving the coupled mode equations by numerical integration method. The transmission spectra corresponding to single-mode and multi-mode are simulated, respectively. The research provides the theoretical foundation for the optimization design of the long-period fiber grating and its application in the field of the optic fiber sensing and communication.