A wavelength selective switch includes an optical fiber array, a multiplexing/demultiplexing component, and a transmission direction adjustment component. The optical fiber array includes a first optical fiber and at least one second optical fiber. The first offset is used to compensate for a second offset of a diffraction spectrum generated when a plurality of single-wavelength optical signals obtained after an optical input signal is processed by the multiplexing/demultiplexing component arrive at the transmission direction adjustment component, so that the second offset of the diffraction spectrum of the plurality of single-wavelength optical signals arriving at the transmission direction adjustment component is 0 or may be ignored. An optical system has a simple structure, and no optical element needs to be added. This increases optical design freedom, facilitates optical path system commissioning, and reduces reliability risks and costs of subsequent products.

An optical cable includes a single optical connector configured for insertion into an optical receptacle so as to receive optical signals at a plurality of different wavelengths from the optical receptacle, and multiple electrical connectors, configured for insertion into respective electrical receptacles. Each electrical connector includes a transceiver configured to convert the optical signals into electrical output signals for output to an electrical receptacle. The optical cable further includes a plurality of optical fibers, having respective first ends connected together to the single optical connector so as to receive the optical signals. Each of the optical fibers has a respective second end coupled to a respective one of the electrical connectors. Wavelength selection optics are associated with the optical fibers so that the transceiver in each of the electrical connectors receives the optical signals at a different, respective one of the wavelengths.

The present disclosure provides example wavelength selective switch (WSS), wavefront control element, and integrated liquid crystal on silicon (LCoS). One example WSS includes an input port fiber array, a demultiplexing/multiplexing grating group, an output port fiber array, and a beam deflection component group including two beam deflection components and at least one wavefront control element located between the demultiplexing/multiplexing grating group and the beam deflection component group or integrated with the LCoS. At least one beam deflection component is a LCoS. The input port fiber array receives multi-wavelength optical signals. The demultiplexing/multiplexing grating group demultiplexes and outputs the multi-wavelength optical signals. The beam deflection component group deflects the multi-wavelength optical signals to the demultiplexing/multiplexing grating group. The demultiplexing/multiplexing grating group multiplexes the multi-wavelength optical signals to the output port fiber array. The wavefront control element and the LCoS jointly modulate optical signals transmitted through N*M wavelength channels.

Disclosed herein are wavelength-division multiplexing devices using different angles of incidence (AOIs) at the WDM filters to provide for variable placement and orientation of WDM filters and channel ports, thereby decreasing the device footprint and allowing for shorter overall optical signal paths to increase signal performance and reliability. Also disclosed are stacked WDM filters for increased signal isolation.

The invention provides methods and apparatus comprising a multi-wavelength laser source that uses a single unfocused pulse of a low intensity but high power laser over a large sample area to collect Raman scattered collimated light, which is then Rayleigh filtered and focused using a singlet lens into a stacked fiber bundle connected to a customized spectrograph, which separates the individual spectra from the scattered wavelengths using a hybrid diffraction grating for collection onto spectra-specific sections of an array photodetector to measure spectral intensity and thereby identify one or more compounds in the sample.

A polarization volume grating (PVG) includes a bulk, birefringent medium characterized by a plurality of helical structures with helix axes and a periodicity Λ.sub.y and an anisotropic alignment material having a rotatable optical axis, disposed on a top or bottom surface of the medium. The PVG is characterized in that the optical axis of the alignment material has a continuously rotated optical axis orientation in a plane of the material surface and a periodicity Λ.sub.x, wherein the helix axes are normal to the optical axes in the alignment material surface, further wherein the birefringent medium is characterized by a plurality of controllably slanted refractive index planes having a slant angle φ=±arctan (Λ.sub.y/Λ.sub.x) and a Bragg period Λ.sub.B. Fabrication methods are disclosed.

A method for implementing folding M×N wavelength selective switch is provided. A one-dimensional single-mode fiber optic collimator array, a short-focus cylindrical mirror, a first long-focus cylindrical mirror, a retroreflector, a transmission phase diffraction grating, a second long-focus cylindrical mirror, a liquid crystal spatial light modulator, and a liquid crystal graphic loading control system are provided along beam transmission direction. The same set of optical elements is used for incident light and outgoing light by ingenious folding structure. The input port and output port of optical signal are consistent in spatial arrangement, thereby reducing space and improving port utilization. Based on composite liquid crystal chips, a working area of the liquid crystal spatial light modulator is doubled, and a quantity of accommodating ports is greatly increased. A quantity of M×N ports of the WSS can be increased greatly by the above structure and design.

A tunable optical filter is described, utilizing a diffraction grating and a rotating mirror. By incorporating a phase screen, or the combination of a phase screen and a transmission amplitude-modulated mask, located in front of the rotating mirror, or possibly at other locations in the optical path, the selected wavelength's passband spectrum can be shaped in a variety of ways. In particular, the output spectrum of the tunable optical filter can be made flatter within the passband, while maintaining good isolation of adjacent channels or wavelengths.

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.

This application discloses an optical communications apparatus, which may be a reconfigurable optical add/drop multiplexer. An optical deflection component (211) may perform angle deflection on a plurality of first sub-wavelength light beams to obtain a plurality of second sub-wavelength light beams and a plurality of third sub-wavelength light beams, and propagate the plurality of second sub-wavelength light beams to a second optical switch array (205). A third wavelength dispersion component (206) combines the plurality of second sub-wavelength light beams into a second light beam. A first output component (207) outputs the second light beam from a dimension. A second wavelength dispersion component (208) combines the plurality of third sub-wavelength light beams into a third light beam, and makes the third light beam incident to a third optical switch array (209). A second output component (210) outputs the third light beam to drop a signal.