US Patent 11550171 Techniques for phase shifting by a photonic resonator

An interferometer comprises a plurality of waveguide branches comprising a plurality of bus waveguides and a plurality of photonic resonators. A first waveguide branch of the plurality of waveguide branches comprises a first photonic resonator coupled to a first bus waveguide. The first photonic resonator is disposed to couple and circle a first portion of an optical beam at the first photonic resonator to generate a first phase shift of the first portion of the optical beam, where the first phase shift is the same as a second phase shift of a second photonic resonator coupled to a second bus waveguide.