Photonic microwave bandpass filter with negative coefficient based on an optical phase modulator and an optical polarizer

In this paper, a photonic microwave bandpass filter with negative coefficient is investigated. The output light from a phase modulator and a polarization-maintaining fiber (PMF) is sent to the optical polarizer. Negative coefficient is generated due to the optical interference of the two polarization modes using the polarizer. A two-tap microwave bandpass filter with one negative coefficient is demonstrated.