A large-scale 3D fiber cross-connect system is disclosed. The system uses modularized and stackable beam steering units to build input and output arrays that can be expanded to large-scale system of 10001000 ports or more. The disclosure provides a two-mirror configuration that minimizes size of the modular beam steering units. With one mirror being fixed on the propagation path of the optical beam and another mirror steerable in a 2D dimension, an any-to-any switching of the large-scale system may be built by stacking the beam steering units over an appropriate distance.

Optical cross connects and methods for use therewith are described herein. In an embodiment, an optical cross connect includes first and second mirror arrays, first and second light sources that respectively emit first and second color coded light beams (e.g., each of which includes red, green and blue light), and first and second cameras configured to respectively capture first and second color images of the first and second color coded light beams reflected respectively from the first and second mirror arrays. The optical cross connect also includes a controller configured to perform closed loop feedback control of the first and second mirror arrays, based on the first and second color images, when the controller controls how optical signals are transferred between individual optical fibers in a first bundle of optical fibers and individual optical fibers in a second bundle of optical fibers.

A method selects a phase shift profile to be applied to a programmable optical phase shift modulator having an array of pixels. A base stepped phase shift profile for the modulator is selected such that when applied to the modulator, the base stepped phase shift profile allows the modulator to function as a blazed grating steering an optical beam through a prescribed angle. The base stepped phase shift profile has a plurality of segments each extending over a given number of the pixels defining a linear array of pixels. Each segment has first and last pixels in the linear array of pixels. Variations in minimum and maximum luminosity levels among the segments of the base stepped phase shift profile are reduced so that any changes to a slope of each segment arising from reducing the variations in the minimum and maximum luminosity level is maintained below a given amount.

The disclosure provides for a system that includes a plurality of stations equipped for free-space optical communications (FSOC) in a network and a central control system. At least one station in the plurality of stations includes a wavelength selectable switch, an OEO module, and one or more first processors. The one or more first processors are configured to control the wavelength selectable switch, process an electrical signal that is extracted using the OEO module, and communicate with the central control system. The central control system includes one or more second processors that are configured to receive data regarding FSOC communication conditions at the plurality of stations, determine a path between stations through the network based on the received data, and transmit instructions to the plurality of stations.

Described herein is a calibration system (25) for a wavelength selective switch (1). The switch (1) is adapted for dynamically switching optical beams (5, 7) along respective trajectories between input and output ports disposed in an array (3) using a reconfigurable Liquid crystal on silicon (LCOS) spatial light modulator device (17). The calibration system (25) includes a monitor (27) for projecting an optical monitor beam (29) through at least a portion of the switch (1) onto the LCOS (17) and detecting the monitor beam (29) reflected from the LCOS (17). In response, system (25) provides a calibration signal (33) to an active correction unit (35) for applying a correction to one or more of the trajectories while maintaining a constant switching state in the LCOS (17).

We describe a wavelength division multiplexed (WDM) reconfigurable optical switch, the switch comprising: a set of arrays of optical beam connections, each comprising an array of optical outputs and having an optical input to receive a WDM input optical signal; a first diffractive element to demultiplexed said WDM input optical signal into a plurality of demultiplexed optical input beams, and to disperse said demultiplexed optical input beams spatially along a first axis; first relay optics between said set of arrays of optical beam connections and said first diffractive element; and a reconfigurable holographic array comprising a 2D array of reconfigurable sub-holograms defining sub-hologram rows and columns; wherein said arrays of said set of arrays are at least one dimensional arrays extending spatially in a direction parallel to said first axis and arranged in a column defining a second axis orthogonal to said first axis; wherein said sub-hologram rows are aligned along said first axis, and wherein said sub-hologram columns are aligned along said second axis; wherein a number of said sub-hologram rows corresponds to a number of arrays in said set of arrays; and wherein each sub-hologram row is configured to receive a set of demultiplexed optical input beams at different carrier wavelengths demultiplexed from the optical input for the array of the set of arrays to which the row corresponds; wherein each of said sub-holograms in a sub-hologram row is reconfigurable to steer a respective wavelength channel of the WDM input signal for the array to which the sub-hologram row corresponds, towards a selected said optical output for the array; and wherein each said sub-hologram row is configured to steer the demultiplexed optical input beams for a respective array of the set of arrays of optical beam connections.

Methods and apparatus are provided that configure a wider passband for one or more channels of a wavelength selective switch (WSS). When a wider passband route WSS and a normal width passband select switch are used in combination, crosstalk that may be introduced by the wider passband route WSS can be mitigated. The wider passband WSS can provide a passband that allows a maximum bandwidth of signal to pass on a given channel and avoid signal being attenuated at the channel edges, especially when channels have a reduced channel spacing, such as with 50 GHz spacing.

Described herein is a calibration system (25) for a wavelength selective switch (1). The switch (1) is adapted for dynamically switching optical beams (5, 7) along respective trajectories between input and output ports disposed in an array (3) using a reconfigurable Liquid crystal on silicon (LCOS) spatial light modulator device (17). The calibration system (25) includes a monitor (27) for projecting an optical monitor beam (29) through at least a portion of the switch (1) onto the LCOS (17) and detecting the monitor beam (29) reflected from the LCOS (17). In response, system (25) provides a calibration signal (33) to an active correction unit (35) for applying a correction to one or more of the trajectories while maintaining a constant switching state in the LCOS (17).

Embodiments of the present application provide a method and an apparatus for transmitting an optical signal and a wavelength selective switch. The transmission method includes: performing diffraction processing on an input optical signal, to obtain signal light and crosstalk light. The signal light is output to a target output port in a plurality of output ports. The diffraction processing includes deflecting, in a second direction, a diffraction direction of a part or all of the crosstalk light, so that the part or all of the crosstalk light is output to an area outside the output ports.

An optical communication terminal is configured to operate in two different complementary modes of full duplex communication. In one mode, the terminal transmits light having a first wavelength and receives light having a second wavelength along a common free space optical path. In the other mode, the terminal transmits light having the second wavelength and receives light having the first wavelength. The terminal includes a steering mirror that directs light to and from a dichroic element that creates different optical paths depending on wavelength, and also includes spatially separated emitters and detectors for the two wavelengths. A first complementary emitter/detector pair is used in one mode, and a second pair is used for the other mode. The system also includes at least two ferrules. Each ferrule operates with a single emitter/detector pair. The ferrules are designed to operate interchangeably with either emitter/detector pair.