Tunable dual-bandpass microwave photonic filter based on a single broadband light source

Abstract

In this paper, a tunable dual-bandpass microwave photonic filter (MPF) based on a single broadband light source (BBS) has been proposed and experimentally demonstrated. By cascading two chirped fiber Bragg gratings (CFBG) with different reflection bandwidth and chirp parameter, the different delay of the modulated light signal in the system is introduced and consequently, a MPF with two different passbands can be realized. Two different passbands with the frequency of 6.75 GHz and 16.01 GHz is obtained in the experiment. By changing the free spectral range (FSR) of the Mach Zehnder interferometer (MZI) through an optical tunable delay line (OTDL), the central frequency of the two passbands can be changed. The dual-bandpass MPF presented in this paper is easy to implement and has good tunability and stability.