System and Method for an Optical Phase Shifter

A method of optical phase shifting, the method comprising:

• receiving a first received optical signal;
• shifting, by a first waveguide phase shifter, a phase of a TE polarized component of the first received optical signal by a first phase shift to produce a TE polarized component of a first phase shifted optical signal;
• shifting, by the first waveguide phase shifter, a phase of a TM polarized component of the first received optical signal by a second phase shift to produce a TM polarized component of the first phase shifted optical signal;
• rotating, by a first polarization rotator, the TE polarized component of the first phase shifted optical signal to produce a TM polarized component of a first rotated optical signal;
• rotating, by the first polarization rotator, the TM polarized component of the first phase shifted optical signal to produce a TE polarized component of the first rotated optical signal;
• shifting, by a second waveguide phase shifter, a phase of the TM polarized component of the first rotated optical signal by a third phase shift to produce a TM polarized component of a second phase shifted optical signal;
• and
• shifting, by the second waveguide phase shifter, a phase of the TE polarized component of the first rotated optical signal by a fourth phase shift to produce a TE polarized component of the second phase shifted optical signal, wherein the first waveguide phase shifter, the first polarization rotator, and the second waveguide phase shifter are integrated on a single substrate.

A Mach-Zehnder interferometer comprising:

• an optical splitter comprising
• a first output port, and
• a second output port;
• a first leg optically coupled to the first output port of the optical splitter, wherein the first leg comprises
• a first waveguide phase shifter,
• a second waveguide phase shifter, and
• a first polarization rotator optically coupled between the first waveguide phase shifter and the second waveguide phase shifter;
• a second leg optically coupled to the second output port of the optical splitter;
• and
• an optical combiner comprising
• a first input port optically coupled to the first leg, and
• a second input port optically coupled to the second leg, wherein the first leg and the second leg are integrated on a substrate.