According to examples, an apparatus may include a wavelength division multiplexing (WDM) module including a WDM housing having a WDM front panel and a WDM component housed within the WDM housing. The apparatus may also include an optical time-domain reflectometer (OTDR)/switch module integrated with the WDM module, the OTDR/switch module including an OTDR housing having an OTDR front panel and an OTDR/switch component housed within the OTDR housing. The WDM housing may be connectable with the OTDR housing to cause respective side edges of the WDM front panel and the OTDR front panel to be adjacent to each other when the WDM housing is connected to the OTDR housing.

Disclosed herein is wavelength-division multiplexing (WDM) and demultiplexing with signal entry and exit in a common routing surface to increase channel density. In particular, disclosed is a WDM assembly including a plurality of common ports and a plurality of channel sets having one or more channel ports. The WDM assembly includes a first routing surface with a first WDM passband and a second routing surface offset from the first routing surface. The second routing surface is configured to reflect at least one signal passed through the first routing surface back through the first routing surface at a laterally different location. Optical signal paths of at least a portion of the common ports are parallel to and offset from one another. In certain embodiments, such a configuration may increase channel density and decrease a form factor (e.g., footprint).

This application provides an optical switching apparatus. The apparatus includes: a first optical switch, L first wavelength division multiplexers/demultiplexers, L second wavelength division multiplexers/demultiplexers, a beam generation apparatus connected to the L first wavelength division multiplexers/demultiplexers, and a detection apparatus connected to the L second wavelength division multiplexers/demultiplexers. One of a plurality of multiplexing ports of the first wavelength division multiplexer/demultiplexer is a signal light port, and a remaining multiplexing port is connected to the beam generation apparatus. A plurality of demultiplexing ports of the first wavelength division multiplexer/demultiplexer are connected to the first optical switch. One of a plurality of multiplexing ports of the second wavelength division multiplexer/demultiplexer is a signal light port, and a remaining multiplexing port is connected to the detection apparatus. A plurality of demultiplexing ports of the second wavelength division multiplexer/demultiplexer are connected to the first optical switch.

To generate, in an optical transmission device, a response signal corresponding to executed control even when said optical transmission device does not comprise one or both of a main signal photoelectric conversion function and a main signal optical amplification function, an optical transmission device comprises: an extraction unit that outputs, from a first optical signal including a main signal and a control signal, a signal including control information included in the control signal; a control unit that executes control on the basis of the control information; and a response signal output unit that outputs, according to the control, a response signal in a wavelength band different from the main signal.

A free-space optical communication system has a conversion assembly, a fiber array, and a wavelength selective switch (WSS) assembly. The conversion assembly converts circular polarization states of incoming optical signals to linear polarization states and converts linear polarization states to circular polarization states for outgoing optical signals. The fiber array has polarization-maintaining (PM) optical fibers arranged in optical communication between the conversion assembly and the WSS assembly to preserve the linear polarization states of the optical signals. The WSS assembly has free-space optics, such as dispersion element and beam-steering element, with optical axes arranged relative to the PM optical fibers. The WSS assembly selectively switches WDM channels of the optical signals relative to the PM optical fibers. Fast and slow axes of the PM optical fibers are aligned to the optical axes of the free-space optics.

An example system includes a first network device having first circuitry. The first network device is configured to perform operations including receiving data to be transmitted to a second network device over an optical communications network, and transmitting first information and second information to the second device. The first information is indicative of the data, and is transmitted using a first communications link of the optical communications network and using a first subset of optical subcarriers. The second information is indicative of the data, and is transmitted using a second communications link of the optical communications network and using a second subset of optical subcarriers. The first subset of optical subcarriers is different from the second subset of optical subcarriers.

An example system includes a first network device having first circuitry. The first network device is configured to perform operations including receiving data to be transmitted to a second network device over an optical communications network, and transmitting first information and second information to the second device. The first information is indicative of the data, and is transmitted using a first communications link of the optical communications network and using a first subset of optical subcarriers. The second information is indicative of the data, and is transmitted using a second communications link of the optical communications network and using a second subset of optical subcarriers. The first subset of optical subcarriers is different from the second subset of optical subcarriers.

Photonic interposers that enable low-power, high-bandwidth inter-chip (e.g., board-level and/or rack-level) as well as intra-chip communication are described. Described herein are techniques, architectures and processes that improve upon the performance of conventional computers. Some embodiments provide photonic interposers that use photonic tiles, where each tile includes programmable photonic circuits that can be programmed based on the needs of a particular computer architecture. Some tiles are instantiations of a common template tile that are stitched together in a 1D or a 2D arrangement. Some embodiments described herein provide a programmable physical network designed to connect pairs of tiles together with photonic links.

A control apparatus for registering a connection state between component devices constituting a distributed optical transmission apparatus in a database includes: a device setting unit which performs setting such that light is output from a component device that is a connection source; and a registration processing unit which acquires a light reception level of each port in each component device on a side receiving the light, identifies a port having a light reception level higher than light reception levels of other ports, and registers a component device having the identified port and the identified port in the database as a connection destination of the component device that is the connection source.

An example system includes a first network device having first circuitry. The first network device is configured to perform operations including receiving data to be transmitted to a second network device over an optical communications network, and transmitting first information and second information to the second device. The first information is indicative of the data, and is transmitted using a first communications link of the optical communications network and using a first subset of optical subcarriers. The second information is indicative of the data, and is transmitted using a second communications link of the optical communications network and using a second subset of optical subcarriers. The first subset of optical subcarriers is different from the second subset of optical subcarriers.