Provided is a polarization-combining module in which it is possible to suppress deviation of an optical axis in a polarization-combining optical system and to perform efficient polarization combination with a less optical loss.

A polarization-combining module includes: a PBS 4 which combines two linearly polarized lights input and emits the combined light; a λ/2 wavelength plate 3 which is provided on an optical path of at least one of the two linearly polarized lights which are input to the PBS 4, and provides polarization rotation by a predetermined angle to the linearly polarized light that passes therethrough; and a pedestal member 10 on which the λ/2 wavelength plate 3 and the PBS 4 are mounted, in which the pedestal member 10 has a protrusion part 12 which defines mounting positions of the λ/2 wavelength plate 3 and the PBS 4 so as to be separated from each other and be parallel to each other, and the λ/2 wavelength plate 3 and the PBS 4 are mounted on the pedestal member 10 with apart of each of the λ/2 wavelength plate 3 and the PBS 4 being brought into contact with the protrusion part 12.

Devices and systems to perform optical alignment by using one or more liquid crystal layers to actively steer a light beam from an optical fiber to an optical waveguide integrated on a chip. An on-chip feedback mechanism can steer the beam between the fiber and a grating based waveguide to minimize the insertion loss of the system.

An apparatus includes an input coupler configured to receive light excited by a light source. A near-field transducer (NFT) is positioned at a media-facing surface of a write head. A layered waveguide is positioned between the input coupler and the NFT and configured to receive the light output from the input coupler in a transverse electric (TE) mode and deliver the light to the NFT in a transverse magnetic (TM) mode. The layered waveguide comprises a first layer extending along a light-propagation direction. The first layer is configured to receive light from the input coupler. The first layer tapers from a first cross track width to a second cross track width where the second cross track width is narrower than the first cross track width. The layered waveguide includes a second layer that is disposed on the first layer. The second layer has a cross sectional area in a plane perpendicular to the light propagation direction that increases along the light propagation direction. The cross sectional area of the second layer is smaller proximate to the input coupler and larger proximate to the NFT.

An optical system includes an optical waveguide, and a first optical element configured to direct a first ray, having a first circular polarization and impinging on the first optical element at a first incidence angle, in a first direction so that the first ray propagates through the optical waveguide via total internal reflection toward a second optical element. The first optical element is configured to also direct a second ray, having a second circular polarization that is distinct from the first circular polarization and impinging on the first optical element at the first incidence angle, in a second direction that is distinct from the first direction so that the second ray propagates away from the second optical element. The second optical element is configured to direct the first ray propagating through the optical waveguide toward a detector.

An optical system includes an optical waveguide, and a first optical element configured to direct a first ray, having a first circular polarization and impinging on the first optical element at a first incidence angle, in a first direction so that the first ray propagates through the optical waveguide via total internal reflection toward a second optical element. The first optical element is configured to also direct a second ray, having a second circular polarization that is distinct from the first circular polarization and impinging on the first optical element at the first incidence angle, in a second direction that is distinct from the first direction so that the second ray propagates away from the second optical element. The second optical element is configured to direct the first ray propagating through the optical waveguide toward a detector.

A tunable optical filter integrates the functions of wavelength tuning and power isolation of back reflection. The optical signal enters a Faraday rotator twice, and isolation is provided by two birefringent crystals, having their optical axes oriented at 45 degrees with respect to each other. The two birefringent crystals are on the same side of the Faraday rotator. The integration of an optical tunable filter and an isolator function into a single packaged component helps to reduce the size and complexity of optical amplifier systems, such as EDFAs and PDFAs, operating in the 1550 nm and 1310 nm transmission bands, respectively.

A digital-electrical to analog-optical converter for converting a N-bit digital data signal uses a non-linear optical element that is susceptible to the Kerr effect. N digitally modulated optical bit stream sources are co-polarized and modulated according to individual bit streams of the digital data. The co-polarized digitally modulated signals interact with a polarized probe signal in the optical element causing the polarization of the probe signal to be changed. Propagating the polarization-changed probe signal output from the optical element through a polarizer provides an amplitude modulated optical signal corresponding to the N-bit digital signal.

Medical imaging camera head devices and methods are provided using light captured by an endoscope system or other medical scope or borescope. Afocal light from the scope is manipulated and split by a beamsplitter. At least one polarizing optical element manipulates the polarization properties of one or both of the beams. The resulting first and second beams are passed through focusing optics to different image sensor areas to produce images with different intensity. The resulting images are combined with high dynamic range techniques.

An optical assembly maintains 90° polarization rotation. In one aspect, an optical assembly includes a polarization beam splitter a rotational element and a path exchange mirror. The temperature, wavelength and manufacturing dependencies of polarization rotation of this optical assembly are minimal to nonexistent compared to conventional Faraday rotation assemblies as the optical fiber accepts only the desired rotation. As such these optical assemblies have no temperature and wavelength dependencies of the polarization rotation angle over broad temperature and wavelength ranges with minimal additional losses. In another aspect, the polarization dependence of reflection from the path exchange mirror is managed so as to minimize the polarization effect associated with oblique incidence.

A system can include a splitter configured to receive a first optical signal carrying first data and generate a first optical signal copy and second optical signal copy. Also included is at least one optical processing path includes at least one optical encoder configured to transform the first optical signal copy into a second optical signal carrying the first data and an additional optical feature not present in the first optical signal, at least one optical modulator configured to optically modulate the second optical signal according to a compare data to generate an optical match signal that indicates matches between the compare data and the first data, and at least one photodetector configured to generate an electrical match signal in response to the optical match signal. Corresponding methods are also disclosed.