Novel flat multichannel filter based on fiber Bragg grating and phase shift

In this letter, a novel optical fiber filter based on fiber Bragg grating and phase shift is proposed for wavelength-division-multiplexing (WDM) system applications. As the channel-space of the comb filter based on chirped sampled fiber Bragg grating and phase shift was not accurate and the multi-channel was unable to channel the standard frequency, we discussed and calculated the error between theory and practice which has certificated by simulation. Then a compensatory method with phase shift between the samples was proposed, and a 80-channel comb filter with accurate 50-GHz channel-spacing was simulated, which is a good foundation for fabricating comb filters with accurate transmission peak in future.