According to an example, a polarization control system is to manipulate polarization manipulators to output light that achieves a trajectory on a Poincar sphere that tracks a known trajectory of a polarizer on the Poincar sphere, in which the trajectory of the output light enables definition of a reference polarization state of the output light. The polarization control system may also manipulate an output polarization manipulator to set the output light to a predefined polarization state based upon the reference polarization state.

A method for adjusting an optical source used for fabricating an optical receiver comprising a signal beam input port, a polarization beam splitter, and signal generation units, is disclosed. The optical source generates a reference beam by combining first and second beams having polarization directions orthogonal each other. The reference beam is introduced to the signal beam input port to measure a first size of an electric signal generated in one of the signal generation units. A half-wavelength plate is disposed on an optical path between the input port and the beam splitter. After that, the reference beam is introduced to the signal beam input port to measure a second size of an electric signal generated in the one of the generation units. At least one of the first and second beams is adjusted such that the first size and the second size become close to each other.

A light source device is provided with: a first laser device that emits a first laser light; a second laser device that emits a second laser light, with the second laser light having an optical axis extending substantially parallel to an optical axis of the first laser light; a first optical axis translator that translates the optical axis of the first laser light; and a second optical axis translator that translates the optical axis of the second laser light A distance between the optical axis of the first laser light before translation and the optical axis of the second laser light before translation is greater than a distance between the optical axis of the first laser light after translation and the optical axis of the second laser light after translation.

The present invention relates to a Bell state measurement apparatus capable of increasing a probability in which a determination that a Bell state measurement fails by using an optical fiber.

Various embodiments relate to polarization splitters. A polarization splitter may include a silicon nitride (SiN) waveguide core configured to receive an input light signal having a first polarization mode and a second polarization mode. The polarization splitter may further include a silicon (Si) slot waveguide core disposed proximate the SiN waveguide core. The Si slot waveguide core may include a tapered portion at a first end configured to couple the first polarization mode to the Si slot waveguide.

Embodiments of the present invention provide a liquid crystal grating-based optical switching apparatus, including an input collimator, an input polarization beam splitter, an input quarter-wave plate, a liquid crystal grating, an output quarter-wave plate, an output polarization beam splitter, and an output collimator. A transmission path is selected for an optical signal by changing a voltage of a liquid crystal grating so that the optical signal is output to a selected output.

Embodiments of the present invention provide a liquid crystal grating-based optical switching apparatus, including an input collimator, an input polarization beam splitter, an input quarter-wave plate, a liquid crystal grating, an output quarter-wave plate, an output polarization beam splitter, and an output collimator. A transmission path is selected for an optical signal by changing a voltage of a liquid crystal grating so that the optical signal is output to a selected output.

An object is to provide an optical coupling system having a simplified structure and a small size and an optical communication device using the optical coupling system. The object is achieved by an optical coupling system that couples a multi-core fiber and coupled devices to each other using a combination of a polarized light beam control element facing a light incident and emission surface of a multi-core fiber and a polarization-selective diffraction element that is positioned on a side of the polarized light beam control element opposite to the emission surface of the multi-core fiber and that faces the coupled devices.

Various embodiments relate to polarization splitters. A polarization splitter may include a silicon nitride (SiN) waveguide core configured to receive an input light signal having a first polarization mode and a second polarization mode. The polarization splitter may further include a silicon (Si) slot waveguide core disposed proximate the SiN waveguide core. The Si slot waveguide core may include a tapered portion at a first end configured to couple the first polarization mode to the Si slot waveguide.

An example system may include a first vertical cavity surface emitting laser (VCSEL) that includes a first integrated polarization locking structure to produce a polarized optical data signal. The system may also comprise a second VCSEL that includes a second integrated polarization locking structure, the second integrated polarization locking structure orthogonal to the first integrated polarization locking structure, to produce an orthogonally polarized optical data signal. Lenses may be disposed on the substrate opposite the first VCSEL, to collimate the polarized optical data signal, and opposite the second VCSEL to collimate the orthogonally polarized optical data signal. A polarization division multiplexer may combine the first collimated polarized optical data signal and the second collimated orthogonally polarized optical data signal.