2π microwave photonic phase shifter based on single semiconductor optical amplifier

A full tunable microwave photonic phase shifter involving a single semiconductor optical amplifier (SOA) is proposed and demonstrated. It is shown that the optical filtering phase characteristic can be advantageously employed to switch between slow and fast light regimes. 360° phase shift has been achieved using two different optical powers at the SOA input by properly adjusting the frequency detuning between the optical notch filter and the optical carrier. Numerical calculations corroborate the experimental results showing an excellent agreement.