Tunable optical frequency comb generator

A method of use, comprising:

• forming a sequence of evenly spaced optical carrier frequencies, including:
• transmitting an optical carrier into an input optical coupler of an interferometer, the interferometer including:
• an input optical coupler, an output optical coupler, and first and second optical waveguide arms located on a substrate, the first and second optical waveguide arms connecting respective first and second outputs of the input optical coupler to respective first and second inputs of the output optical coupler, wherein the first optical waveguide arm includes a first optical phase shifter and a first adjustable optical phase modulator, and the second optical waveguide arm includes a second adjustable optical phase modulator;
• re-circulating a portion of the optical carrier through the interferometer via an optical feed-back loop waveguide, the optical feed-back loop waveguide having one end connected to a first output of the output optical coupler and having another end connected to a first input of the input optical coupler;
• and
• driving at least one of the optical phase modulators with a periodic electrical signal.