A microwave photonic phase-shifter based on wavelength conversion in a DFB laser

We propose and demonstrate a microwave photonic phase-shifter using a distributed-feedback laser-wavelength converter. Through carrier competition in the laser, information is passed from the input signal to the lasing mode. The frequency response of this conversion mechanism follows the intrinsic modulation response of the laser, which exhibits a large phase change near the relaxation frequency. Through current-control of the relaxation frequency, the phase of the wavelength-converted microwave output can be varied by more than 135deg over a bandwidth of 1.8GHz. We further identify an operating regime that exhibits a large discrete phase shift of 114deg at 3 GHz with negligible change in power