Integrated microwave photonics phase shifter using on-chip stimulated Brillouin scattering

In this paper we consider two new topologies of a tunable microwave photonic phase shifter using stimulated Brillouin scattering. In the first topology, independent phase and amplitude control of an optical carrier was achieved by controlling two SBS pumps in an optical fiber leading to a record demonstration of 360° continuously tunable phase shift, with less than 0.25 dB output power fluctuations, over a frequency band from 1.5 to 31 GHz. In the second topology, the first integrated phase shifter using SBS on chip was demonstrated. We highlight an advantage of a shorter integrated platform compared to a long length of optical fibers, which is a higher pump depletion threshold that leads to a greater potential for reducing the phase shifter insertion loss.