Abstract: A reconfigurable optical add and drop multiplexer (ROADM) system is provided. The ROADM system may include a switching system which includes at least one first WSS optically coupled to a tapping coupler and configured to receive an input optical signal from a first circulator, transmit a drop optical signal to a demultiplexer to drop one or more first wavelength channels, and output a through optical signal. The switching system may also include at least one second WSS optically coupled to the at least one first WSS and a multiplexer and configured to receive an add optical signal to add one or more second wavelength channels, receive the through optical signal, and output an output optical signal to a second circulator, and at least one OCM configured to monitor the input optical signal and the output optical signal.

Abstract: 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.

Abstract: Embodiments of the present invention provide a variable optical attenuator. The variable optical attenuator includes: a collimator, a switchable polarization grating, a reflector, and a voltage controller for adjusting a voltage between electrodes at both ends of a liquid crystal layer of the switchable polarization grating, where the collimator, the switchable polarization grating, and the reflector are disposed successively; the collimator is configured to receive incident light and output the incident light to the switchable polarization grating; the switchable polarization grating is configured to diffract the incident light for one time and then perform emission onto the reflector; the switchable polarization grating is further configured to diffract, for one time, a beam reflected back by the reflector, and then emit resulting diffracted light; and the collimator is further configured to receive the diffracted light and output the diffracted light.

Abstract: Embodiments of the present invention provide a variable optical attenuator. The variable optical attenuator includes: a collimator, a switchable polarization grating, a reflector, and a voltage controller for adjusting a voltage between electrodes at both ends of a liquid crystal layer of the switchable polarization grating, where the collimator, the switchable polarization grating, and the reflector are disposed successively; the collimator is configured to receive incident light and output the incident light to the switchable polarization grating; the switchable polarization grating is configured to diffract the incident light for one time and then perform emission onto the reflector; the switchable polarization grating is further configured to diffract, for one time, a beam reflected back by the reflector, and then emit resulting diffracted light; and the collimator is further configured to receive the diffracted light and output the diffracted light.

Abstract: 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.

Abstract: The present invention discloses a beam processing device, a beam attenuation and switching device, and an optical wavelength selective switch system. The beam processing device in the present invention includes a polymer polarization grating and a quarter-wave plate array. Splitting and adjustment of a beam polarization state may be implemented by using the polymer polarization grating and the quarter-wave plate array. The beam attenuation and switching device includes a switchable polarization grating and an optical path angle adjustment device, or includes a half-wave liquid crystal plate, a quarter-wave plate, a polymer polarization grating, and an optical path angle adjustment device.

Abstract: Apparatus and method embodiments are provided for implementing a wavelength selective switch (WSS). The embodiments use combinations of switchable polarization grating (SPG) and LC cells and combinations of polymer polarization grating (PPG) and LC cells to achieve 1×N WSS systems. An embodiment optical switch includes a liquid crystal cell and a polymer polarization grating (PPG) cell adjacent to the liquid crystal cell. The PPG includes a glass substrate, a photo-alignment layer overlying the glass substrate and comprising photosensitive polymer that has been physically altered by exposure using two interfering light beams with opposite handedness of circular polarization, and a polymerized liquid crystal layer overlying the photo-alignment layer on an opposite side of the glass substrate, the polymerized liquid crystal layer has been physically altered by illumination using a uniform light beam.

Abstract: Apparatus and method embodiments are provided for implementing a wavelength selective switch (WSS). The embodiments use combinations of switchable polarization grating (SPG) and LC cells and combinations of polymer polarization grating (PPG) and LC cells to achieve 1×N WSS systems. An embodiment optical switch includes a liquid crystal cell and a polymer polarization grating (PPG) cell adjacent to the liquid crystal cell. The PPG includes a glass substrate, a photo-alignment layer overlying the glass substrate and comprising photosensitive polymer that has been physically altered by exposure using two interfering light beams with opposite handedness of circular polarization, and a polymerized liquid crystal layer overlying the photo-alignment layer on an opposite side of the glass substrate, the polymerized liquid crystal layer has been physically altered by illumination using a uniform light beam.

Abstract: Apparatus and method embodiments are provided for implementing a wavelength selective switch (WSS). The embodiments use combinations of switchable polarization grating (SPG) and LC cells and combinations of polymer polarization grating (PPG) and LC cells to achieve 1×N WSS systems. An embodiment optical switch includes a liquid crystal cell and a SPG cell adjacent to the liquid crystal cell. The SPG includes liquid crystal material between two photo-alignment layers, an electrode layer overlying each photo-alignment layer, and a glass substrate overlying each electrode layer. An embodiment method includes polarizing an incident light beam at a circular polarization before diffracting, at a polarization grating, the polarized incident light beam in a determined angle that corresponds to a diffraction order in accordance to the circular polarization of the incident light beam and a hologram pattern direction formed inside the polarization grating.

Abstract: An optical device for processing an optical signal includes a crystal wedge, a polarization modulator, and a reflective element. The crystal wedge spatially separates an input optical signal into a first beam component having a first polarization state and a second beam component having a second polarization state. The crystal wedge has an optical axis arranged at an optical axis angle such that the first beam component and the second beam component converge. The polarization modulator changes the polarization state of the first beam component and the polarization state of the second beam component in response to a control signal. The reflective element reflects the first beam component and the second beam component such that the crystal wedge spatially recombines a portion of the first beam component having the second polarization state with a portion of the second beam component having the first polarization state to form an output optical signal.