A single passband microwave photonic filter with flat-top and steep transition edges

We propose and experimentally demonstrate a microwave photonic filter based on an electro-optic phase modulator (EOPM) and a Fabry–Pérot semiconductor optical amplifier (FP-SOA). A microwave photonic filter with a single passband between 0 and 40 GHz is obtained. The center frequency, the −3 dB bandwidth and the −30 dB bandwidth of the microwave photonic filter are 18.3, 3.184 and 4.005 GHz respectively. Correspondingly, the shape factor, which is defined as the ratio of the −30 dB bandwidth to the −3 dB bandwidth, is 1.26, and the Q factor, which is defined as the ratio of center frequency to the −3 dB bandwidth of the microwave passband, is 5.75. The achieved microwave passband can be fitted by an 8th order super-Gaussian shape.