<p>In one embodiment，an optical phase shifter includes a first phase-shifter configured to phase shift a transverse electric (TE) component of an optical signal by a first phase-shift to produce a TE component of a first signal，and a transverse magnetic (TM) component of the optical signal by a second phase-shift to produce a TM component of the first signal. The optical phase-shifter includes a polarization-rotator configured to rotate the TE component of the first signal to produce a TM component of a rotated signal，and the TM component of the first signal to produce a TE component of the rotated signal. The optical phase-shifter includes a second phase- shifter configured to phase-shift a TE component of the rotated signal by a third phase-shift，and the TM component of the rotated signal by a fourth phase-shift，where the first phase-shifter，the polarization-rotator，and the second phase-shifter are integrated on a substrate.</p>
