High-resolution microwave photonic notch filter with low-noise and low group delay ripple performance

A high-resolution microwave photonic notch filter having a wide passband and a narrow notch, is presented. It is based on a WDM multiple double-pass modulation approach using Bragg grating reflectors. The WDM laser powers are optimised to flatten the filter passband and to improve the filter group delay performance. The filter operates over a wide frequency range, and the notch frequency is tunable. Experimental results demonstrate a microwave photonic notch filter with a wide and flat passband, a narrow notch at GHz frequency and a high signal-to-noise ratio performance. Tunable coherence-free operation of the notch filter is also shown.