Ultrawide Tunable Microwave Photonic Notch Filter Based on Stimulated Brillouin Scattering

A new ultrawide tunable microwave photonic notch filter that exhibits a very high resolution is presented. It is based on a stimulated Brillouin scattering technique, which processes the modulation sidebands generated by a dual-drive Mach-Zehnder modulator. Tuning is realized by changing the drive frequency to an electro-optic intensity modulator. Experimental results demonstrate a high-resolution notch filter with a 3-dB bandwidth of 82 MHz, a notch depth of over 40 dB, a flat passband from near DC to 20 GHz with very low ripples, and a notch frequency that can be continuously tuned with shape invariance over an ultrawide frequency range from 2 to 20 GHz.