First data and second data are transmitted by a simple configuration by including a generation unit that generates a wavelength-changed signal on the basis of the second data, and a transmission unit that transmits the wavelength-changed signal together with a first signal that indicates the first data.

A method and apparatus for communications in a passive optical network (PON) system are provided. An optical line terminal (OLT) generates a PON downstream Physical Layer (PHY) frame comprising a downstream physical synchronization block (PSBd) that comprises a wavelength identification (ID) of at least one downstream wavelength of the plurality of downstream wavelengths. The OLT sends the PON PHY frame comprising the wavelength ID in the PSBd to ONU for confirming the at least one downstream wavelength.

A burden for configurating optical transmission equipment is increased as capacity in an optical transmission system is increased. An optical control device according to the present invention includes a storage means for storing transmission characteristics information in advance, the transmission characteristics information relating to an optical transmission system that transmits signal light via an optical transmission line, a first connection means for receiving the signal light and test light having a wavelength different from that of the signal light, an optical modulation means for modulating the test light by using the transmission characteristics information, and generating test modulation light, and a second connection means for delivering the test modulation light.

In an optical network based on a dense wavelength division multiplexing system using a flexible frequency grid, it is difficult to improve the usage efficiency of an optical frequency band owing to the occurrence of fragmentation of the optical frequency band; therefore, an optical network controller according to an exemplary aspect of the present invention includes an optical frequency region setting means for setting a plurality of optical frequency regions in an optical frequency band used in an optical network based on a dense wavelength division multiplexing system using a flexible frequency grid; an optical path setting means for setting optical paths having a common attribute in at least one of the plurality of optical frequency regions; and an optical frequency region control means for changing an optical frequency width of the optical frequency region, and instructing the optical frequency region setting means to reconfigure, as the plurality of optical frequency regions, a plurality of optical frequency reconfigured regions each of which having the optical frequency width after having been changed.

An optical transmission device that is provided at a first site includes: an optical transmitter that transmits a first optical signal that includes first ID information to a second site using a first wavelength; and an optical receiver that receives a second optical signal that includes second ID information and that is transmitted using the first wavelength from the second site. When the first ID information matches the second ID information, the optical transmitter transmits a wavelength report that indicates a second wavelength to the second site using the first wavelength. When the optical receiver receives a completion report that indicates the wavelength report has been received at the second site, the optical transmitter transmits an optical signal to the second site using the second wavelength, and the optical receiver ceases to receive an optical signal of the first wavelength from the second site.

A method (100) for facilitating Optical Supervisory Channel (OSC) communications between a main site and a plurality of remote sites in an optical network is disclosed. The main and remote sites are comprised within a Radio Access Network and the main and remote sites are connected via a point to multipoint optical infrastructure. The method comprises receiving an OSC signal on an OSC from the main site (120), sequentially routing OSC signals on the OSC to each of the remote sites in a daisy chain configuration (140) and returning an OSC signal received on the OSC from a last of the remote sites in the daisy chain configuration to the main site (160), the OSC being transported over the point to multipoint optical infrastructure (170). Also disclosed are a method (500) for performing OSC communications in an optical network, a hub node (300, 400), a remote site node (600, 800) and a system (900) for communications in an optical network.

Disclosed herein is a method of assigning a wavelength to a given light path in a wavelength switched optical network, as well as a corresponding routing engine and computer program. The method comprises the following step. For each of a plurality of possible wavelengths for said light path, retrieving information from an optical performance database (30) allowing to assess whether the given wavelength meets a predetermined feasibility criterion with regard to said given light path; if the given wavelength is found to meet the predetermined feasibility criterion, determining a set of extended feasible light paths, each of which fully including the given light path, but containing one or more additional nodes; and calculating a first score based on said determined set of extended feasible light paths, wherein said method further comprises a step of choosing, based on said first score, a wavelength that has a first score indicating a low suitability for providing useful extended feasible light paths for future use.

A wavelength reallocation assisting method provides information relating to wavelength allocation to optical lines in a wavelength division multiplexing optical network in which a plurality of nodes are connected by optical fibers. The wavelength reallocation assisting method includes: outputting first allocation state information that indicates a sum of bandwidths of respective wavelength slots used by at least one of the optical lines among a plurality of wavelength slots that are available in the wavelength division multiplexing optical network; and outputting second allocation state information that indicates a maximum value of individual used bandwidths obtained with respect to the respective optical fibers, each of the individual used bandwidths indicating a sum of bandwidths of wavelength slots allocated to corresponding optical lines established in a corresponding optical fiber.

A communication apparatus for a fiber-optic communication system for an aircraft that includes: an optical coupler; an input port optically coupled to the optical coupler via a first waveguide, the input port arranged to receive light; a modulator optically coupled to the optical coupler via a second waveguide, the modulator having a logic input and a fiber having a fiber Bragg grating (FBG) receiving light from the input port via the optical coupler, the modulator operable to vary a strain force applied to the fiber according to a logic signal received at the logic input to modulate a wavelength of a modulated light signal reflected by the FBG back to the optical coupler; and an output port optically coupled to the optical coupler via a third waveguide to receive the modulated light signal therefrom, the output port being operable to output the modulated light signal.

A proactive and non-obtrusive channel probing scheme is provided to accurately predict channel power, gain, and optical signal to noise ratio (OSNR) without disrupting the existing connections. In one example, using a probe signal with 5 s pulse duration in a single-hop network, rapid wavelength switching is achieved with power excursions less than or equal to 0.2 dB for different loading configurations.