Phase modulator for optical signal using multimode interference couplers

A method of outputting an optical modulated signal comprising the steps of:

• providing a multimode interference (MMI device) having at least two inputs and at least one output;
• providing a first input signal to a first one of the at least two inputs, and a second input signal to a second one of the at least two inputs
• configuring a phase difference between the first input signal and the second input signal by coupling the MIMI device within a resonator, wherein relative phase between the first input signal and the second input signal is fixed;
• and
• modulating the input power of at least one of the at least two inputs to produce a modulated signal at the at least one output of the MMI.

An optical resonator configured to output a modulated signal, the optical resonator comprising:

• a first multimode interference (MMI) device having at least two inputs;
• a second MMI device having at least one input coupled to an output of the first MMI device,
• wherein relative phase between the at least two inputs of the first MMI device is fixed by a phase difference configured using the second MMI device, and
• wherein input power of one of the at least two inputs of the first MMI device is modulated to produce a modulated signal at the output of the first MMI.