Methods and devices for inter-spacecraft optical communication are described. The device includes a transmitter for generating a first multi-wavelength signal composed of a first set of wavelengths; a receiver for detecting a second multi-wavelength signal composed of a second set of wavelengths mutually exclusive from the first set of wavelengths; at least one first optical component configured for propagating the first multi-wavelength signal into free space and for capturing the second multi-wavelength signal from free space, the first and second multi-wavelength signals propagating collinearly in free space in opposite directions; and at least one second optical component coupled between the transmitter, the receiver, and the at least one first optical component, and configured for discriminating between the first multi-wavelength signal and the second multi-wavelength signal and redirecting the first multi-wavelength signal to the at least one first optical component and the second multi-wavelength signal to the receiver.

A bi-directional optical transceiver module includes: an optical transmission unit to output a transmission signal; an optical reception unit to receive a reception signal, the transmission signal and the reception signal having different corresponding first and second wavelength values within a single channel; a splitter, inclined with respect to an incident direction of the transmission signal output from the optical transmission unit, to transmit the transmission signal to an outside, and reflect optical signals input from the outside, the optical signals including the reception signal; and a reflected light-blocking optical filter unit to pass, as the reception signal among the optical signals reflected by the splitter, an optical signal within a preset wavelength range including the second wavelength value.

A dense wavelength-division multiplexing (DWDM) optical network includes an optical input port configured to receive unmodulated optical signals from the optical fiber comprising wavelength channels; one or more modulators coupled to the optical input port wherein the one or more modulators are each configured to modulate a respective first wavelength channel of the wavelength channels with respective data to produce a modulated first wavelength channel when the modulator is in a transmit state; wherein an input optical power of each modulator is kept at substantially a first level and an output optical power of the each modulator is kept at substantially a second level during operation of the modulator. A method and an optical network node are also disclosed therein.

A method may include transmitting, by an optical device, a first channel. The first channel may have a first set of subcarriers. The first channel may be attenuated during transmission by a filter associated with a wavelength selective switch. The method may further include transmitting, by the optical device, a second channel. The second channel may have a second set of subcarriers. The second channel may be attenuated during transmission by the filter associated with the wavelength selective switch. The first channel and the second channel being included in a super-channel. The first set of subcarriers may be selected based on a first signal quality factor associated with attenuation of the first set of subcarriers by the filter. The second set of subcarriers may be selected based on a second signal quality factor associated with attenuation of the second set of subcarriers by the filter.

In an example, a communication module includes an optical transmitter, an optical receiver, and a periodical filter. The optical transmitter is configured to emit an outbound optical signal. The optical receiver is configured to receive an inbound optical signal. A first frequency of the outbound optical signal is offset from a second frequency of the inbound optical signal by an amount less than a channel spacing of a multiplexer/demultiplexer implemented in an optical communication system that includes the communication module. The periodical filter is positioned in optical paths of both the outbound optical signal and the inbound optical signal and has a transmission spectrum with periodic transmission peaks and troughs. The first frequency of the outbound optical signal may be aligned to one of the transmission peaks and the second frequency of the inbound optical signal may be aligned to one of the transmission troughs, or vice versa.

An electromagnetic signal transport and distribution system simultaneously transports over one single mode fiber various programming specifically requested by multiple users in multiple locations while simultaneously offering bidirectional communications with a public network.

Systems and methods include, for operation on an optical fiber in an optical network with the optical fiber having extended optical spectrum that include a plurality of bands including at least the C-band and one or more additional bands, segmenting the plurality of bands by distance based on different transmission specifications for the plurality of bands based on fiber types and amplifiers used for corresponding bands; and placing one or more channels on the optical fiber in a corresponding band of the plurality of bands based on a distance between nodes associated with each of the one or more channels. The segmenting is based on a metric that is a function of fiber type of the optical fiber and amplifier performance for amplifiers used in the plurality of bands.

A transmission device including a demultiplexer configured to demultiplex a multiplexed light obtained by multiplexing the plurality of wavelength division multiplexing (WDM) optical signals including different wavelength bands into the plurality of WDM optical signals, a plurality of optical amplifiers configured to amplify the plurality of WDM optical signals, respectively, a wavelength converter configured to convert a first wavelength band of the wavelength bands of at least a first WDM optical signal of the plurality of WDM optical signals amplified by the plurality of optical amplifiers into a second wavelength band of the wavelength bands of a second WDM optical signal of the plurality of WDM optical signals so that the second wavelength band does not overlap among the wavelength bands, and a multiplexer configured to multiplex the plurality of WDM optical signals which include the wavelength bands converted by the wavelength converter.

Systems and methods include, for operation on an optical fiber in an optical network with the optical fiber having extended optical spectrum that include a plurality of bands including at least the C-band and one or more additional bands, segmenting the plurality of bands by distance based on different transmission specifications for the plurality of bands based on fiber types and amplifiers used for corresponding bands; and placing one or more channels on the optical fiber in a corresponding band of the plurality of bands based on a distance between nodes associated with each of the one or more channels. The segmenting is based on a metric that is a function of fiber type of the optical fiber and amplifier performance for amplifiers used in the plurality of bands.

Systems and methods include, responsive to provisioning a media channel (52) on a degree, wherein the media channel (52) is a contiguous portion of optical spectrum supporting N channels, N is greater than 1, causing allocation of optical filter bandwidth in an optical multiplexing/demultiplexing device for M channels (56) in the media channel (50), where M is less than N; causing provisioning of the M channels (56) in the media channel (50); and causing configuration of channel holders in the media channel from a channel holder source (20) for a part of the portion of the optical spectrum unoccupied by the M channels (56).