Nonlinearly chirped grating based continuously tunable high notch rejection microwave photonic filter

Abstract

We propose a continuously tunable high notch rejection microwave photonic filter which is based on a nonlinearly chirped fibre Bragg grating (NLCFBG). The filter response is caused by the dispersion induced by the NLCFBG and tunability is realized through changing the operating optical wavelength. Measured results demonstrating notch frequency tuning of 4.7 GHz with more than 45 dB notch rejection are presented.

Microwave signal processing using photonic techniques

“…The third MPF aims to achieve high notch rejection. By using the chromatic dispersion (CD) of the nonlinearly chirped fibre Bragg grating (NLCFBG), more than 45 dB notch rejection has been achieved with 4.7 GHz FSR tuning [83]. In all cases, the measured filter response matches the theoretical calculations.…”

“…Since there is only one optical signal, a stable operation is ensured [83]. Zehnder modulator is used here for its zero chirp [59].…”