Fiber-based vector-sum microwave photonic phase shifter

The theory of fiber-based vector-sum microwave photonic phase shifter is investigated. A new structure of the phase shifter is designed and its model is studied. Adjustable optical divider and polarization-maintaining fiber are used in the structure, which can reduce the structural complexity and the coherent interference, and can enhance the controllability of the phase shifter. The effects on the phase and amplitude of the signals of the division factor and the frequency are analyzed. The phase shift above 140 is achieved and the attenuation of the amplitude of the signals can be compensated by power amplifier.