An optical integrated circuit includes: a mode conversion and branching section that launches light from a first optical waveguide to a second optical waveguide, converts light from the first optical waveguide into converted light, and launches the converted light to a third optical waveguide; an optical multiplexing and branching section that multiplexes lights from the second and third optical waveguides into one multiplexed light component, and branches the multiplexed light component into a light component to be input to a fourth optical waveguide and a light component to be input to a fifth optical waveguide; a phase modulation section that is provided in at least one of the fourth and fifth optical waveguides and modulates a phase of guided light; and an optical multiplexing section that multiplexes light components from the fourth and fifth optical waveguides into one light component.

Advantageously, at least one embodiment of the present disclosure comprises a polarization maintaining PROFA (“PM-PROFA”) coupler in which the polarization axes of the individual vanishing core waveguides thereof are oriented or aligned without the need to adjust the orientation of each individual VC waveguide.

Photonic rotators integrated on a substrate are disclosed for manipulating light polarization.

An optical apparatus for compensating a measurement inaccuracy of polarization dependent loss (PDL) is described. The apparatus comprises a first polarization rotator splitter (PRS) for splitting an input beam into orthogonally polarized X and Y component beams and rotating one of the X and Y component beams to be in the same polarization as the other component beam; first and second circuits for processing the X and Y component beams respectively; a first polarization rotator combiner (PRC) for combining the X and Y component beams processed respectively by the first and second circuits into an output beam, one of the X and Y component beams being rotated to be orthogonally polarized with respect to the other component beam. The apparatus further comprises a first set of photodetectors for monitoring a first relative power between the X and Y component beams before the first and second circuits; a second set of photodetectors for monitoring a second relative power between the X and Y component beams processed respectively by the first and second circuits; and complementary PRSs and PRCs coupled between the first and second circuits and the second set of photo-detectors for compensating a measurement inaccuracy of PDL caused by the first PRS and PRC.

Embodiments herein relate to photonic integrated circuits with an on-chip optical isolator. A photonic transmitter chip may include a laser and an on-chip isolator optically coupled with the laser that includes an optical waveguide having a section coupled with a magneto-optic liquid phase epitaxy grown garnet film. In some embodiments, a cladding may be coupled with the garnet film, the on-chip isolator may be arranged in a Mach-Zehnder interferometer configuration, the waveguide may include one or more polarization rotators, and/or the garnet film may be formed of a material from a rare-earth garnet family. Other embodiments may be described and/or claimed.

A state of polarization (SOP) controller allows a randomly polarized input beam to be converted to a single linear polarization, while transferring substantially all of the power to the output. The input beam is split into orthogonal components and one of the components rotated and a phase difference between the components compensated for. The phase aligned components may then be recombined into a single output. The phase shifters may be reset during a reset period during which the impact on data transmission is reduced.

A polarization scrambler based on Faraday magneto-optic effect is disclosed. A polarization control unit (2) is connected between a first rotator unit (1) and a second rotator unit (3). The first rotator unit (1) includes a first optical fiber circle (11) and a first wire coil (12). The second rotator unit (3) includes a second optical fiber circle (31) and a second wire coil (32). ACs with two frequencies f1 and f2 are respectively introduced into the first wire coil (12) and the second wire coil (32), such that the ACs in the two wire coils are changed to control the polarization angle in the two optical fiber circles to independently change within the range of +/−90°. The polarization control unit (2) can ensure motion trajectories of outputted light polarization pointsare in two orthogonal directions, thus achieving uniform polarization disturbance.

In order to provide a configuration for suppressing deterioration in the transmission quality of a signal light due to a nonlinear phenomenon in an optical fiber, a polarization dispersion adder is provided with: a polarization rotation unit which, with respect to each pulse of signal light generated by modulating a light carrier, rotates and outputs the polarization of the pulse during a period from a pulse rise start time (T0) to a pulse fall completion time (T1); and a delay addition unit which adds a delay of an amount corresponding to the rotation amount of the polarization added by the polarization rotation unit to the pulse outputted from the polarization rotation unit.

A wavelength converter includes a polarization beam splitter configured to separate input light into a first polarization and a second polarization that are orthogonal to each other a non-linear optical medium configured to include a first incident end on which the first polarization separated by the polarization beam splitter is incident and a second incident end on which the second polarization separated by the polarization beam splitter is incident at a position different from a position of the first incident end, an optical multiplexer configured to multiplex the first polarization that has passed through the non-linear optical medium and the second polarization that has passed through the non-linear optical medium, and an optical element arranged between the non-linear optical medium and the optical multiplexer, and configured to correct a polarization axis of at least one of the first polarization and the second polarization incident on the optical multiplexer.

An electro-optic receiver includes a polarization splitter and rotator (PSR) that directs incoming light having a first polarization through a first end of an optical waveguide, and that rotates incoming light from a second polarization to the first polarization to create polarization-rotated light that is directed to a second end of the optical waveguide. The incoming light of the first polarization and the polarization-rotated light travel through the optical waveguide in opposite directions. A plurality of ring resonators is optically coupled the optical waveguide. Each ring resonator is configured to operate at a respective resonant wavelength, such that the incoming light of the first polarization having the respective resonant wavelength optically couples into said ring resonator in a first propagation direction, and such that the polarization-rotated light having the respective resonant wavelength optically couples into said ring resonator in a second propagation direction opposite the first propagation direction.