A method is described in which a loss of spectrum in an optical signal having an optical signal spectrum is detected. The optical signal is transmitted from a first node to a second node. In response to detecting the loss of spectrum in the optical signal, at least one idler carrier without data imposed is supplied into the optical signal spectrum transmitted from the first node to the second node, the optical signal spectrum encompassing a frequency band including a plurality of optical channels, the idler carrier being amplified stimulated emission light having a frequency corresponding to a first optical channel of the plurality of optical channels.

An optical data transmitter includes vertical cavity surface-emitting lasers and an all-optical spatial mode multiplexer. Each vertical cavity surface-emitting laser is configured to output a data modulated optical carrier at a center wavelength of less than one micrometer. The all-optical spatial mode multiplexer has an optical output and optical inputs. Each vertical cavity surface-emitting lasers is optically connected to one or more of the optical inputs of the all-optical spatial mode multiplexer. The all-optical spatial mode multiplexer is configured to cause at least two of the vertical cavity surface-emitting lasers to excite linearly independent combinations of one or more optical spatial propagating modes of an optical fiber in response to the optical output being coupled to a near end of the optical fiber.

The present application discloses example optical transmission apparatuses, where one example apparatus includes a filter, a router, and an optical multiplexer. The filter is connected to the router, and the router is connected to the optical multiplexer. The filter performs parity optical demultiplexing on 2N input optical signal groups by using 2N comb filters to obtain 2N odd optical signal groups and 2N even optical signal groups, and sends the 2N odd optical signal groups and the 2N even optical signal groups to the router. The router separately routes the 2N odd optical signal groups and the 2N even optical signal groups to the optical multiplexer by using at least four AWGRs. The optical multiplexer performs, by using 2N optical multiplexers, optical multiplexing on 4N optical signal groups output by the router to obtain 2N output optical signal groups.

Optical fiber data communications are described. A comb laser can provide light at a first wavelength and a second wavelength. Using that light, polarization multiplexing circuitry can generate an optical signal having different polarization components and transceivers can transmit the optical signal having the first wavelength and a probe having the second wavelength via an optical fiber. A polarimeter can determine characteristics of the polarization of the probe. Based on the characteristics, a polarization controller can adjust a polarization of the optical signal. The optical signal can then be split into different polarization components.

An optical signal monitor, including: a storage that holds a threshold value set for each of determination areas having a bandwidth set in accordance with an average grid of dummy light; a measurement section that sequentially measures an optical intensity of an inputted wavelength-multiplexed optical signal with respect to each of measurement areas obtained by dividing the determination area into areas with a bandwidth sufficiently smaller than a grid width of a monitoring-target optical signal composing the wavelength-multiplexed optical signal, and output measured values; and a section that determines that dummy light corresponding to the determination area needs introducing if each of measured values in the determination area is smaller than a threshold value, and, determines that dummy light corresponding to the determination area does not need introducing if at least one of the measured values in the determination area is equal to or larger than the threshold value.

An integrated apparatus with optical/electrical interfaces and protocol converter on a single silicon substrate. The apparatus includes an optical module comprising one or more modulators respectively coupled with one or more laser devices for producing a first optical signal to an optical interface and one or more photodetectors for detecting a second optical signal from the optical interface to generate a current signal. Additionally, the apparatus includes a transmit lane module coupled between the optical module and an electrical interface to receive a first electric signal from the electrical interface and provide a framing protocol for driving the one or more modulators. Furthermore, the apparatus includes a receive lane module coupled between the optical module and the electrical interface to process the current signal to send a second electric signal to the electrical interface.

Described herein is a space based subsystem of a satellite, and methods for use therewith, for receiving an optical ISL beam from another satellite, and in dependence therein, producing a further optical ISL beam for transmission to a further satellite. Additionally, the subsystem can also produce RF service downlink beams for transmission to service terminals. The subsystem can include, inter alia, receiver optics, optical amplifiers, a WDM demultiplexer, beam splitters, a WDM multiplexer, and transmitter optics. In certain embodiments, because RF frequencies of a wavelength division multiplexed optical signal produced by the WDM multiplexer are within a same specified RF frequency range within which the satellite and the further satellite are configured to transmit RF service downlink beams, there is an elimination of any need for the satellite and further satellite to perform any frequency conversions when producing the RF service downlink beams in dependence on the optical ISL beams.

Described herein is a ground based subsystem for inclusion in an optical gateway and for use in transmitting an optical feeder uplink beam to a satellite. The subsystem can include a wavelength-division multiplexing (WDM) multiplexer configured to receive optical data signals from optical network(s) external to the ground based optical gateway, and configured to combine the optical data signals into a wavelength division multiplexed optical signal. The subsystem can also include an optical amplifier to amplify the wavelength division multiplexed optical signal, and transmitter optics to receive the amplified wavelength division multiplexed optical signal and transmit an optical feeder uplink beam to the satellite in dependence thereon. In certain embodiments, the ground based optical gateway does not perform any modulation or demodulation of the optical data signals received from the optical network(s) external to the ground based optical gateway before they are provided to the WDM multiplexer.

Methods, systems, and devices are disclosed for using optical modes in optical waveguides to carry different optical communication signals. In one aspect, an optical device for optical MDM in optical communications includes an optical waveguide configured to support multiple optical waveguide modes and to carry light of different optical communication channels in different optical waveguide modes, respectively, of the multiple optical waveguide modes. The optical device includes an optical resonator configured to be capable of carrying an optical communication channel in one optical resonator mode and optically coupled to the optical waveguide to selectively couple the optical communication channel in the optical resonator into the optical waveguide to add a channel into the optical waveguide via optical mode division multiplexing. In another aspect, an optical mode division demultiplexing can be performed by coupling an optical waveguide and an optical resonator.

An optical signal transmission apparatus includes: a first fiber collimator, configured to input a first combined optical signal; a first beam splitter, configured to split the first combined optical signal to obtain an optical signal of a first wavelength and an optical signal of a second wavelength, transmit the optical signal of the first wavelength to a first filter unit, and transmit the optical signal of the second wavelength to a third fiber collimator; the first filter unit, configured to transmit the optical signal of the first wavelength to the third fiber collimator; a second fiber collimator, configured to input an optical signal of a third wavelength; a second filter unit, configured to transmit the optical signal of the third wavelength to the third fiber collimator; and the third fiber collimator, configured to output a second combined optical signal.