An optical signal adjustment unit (1) is configured in such a way that optical signals with different wavelengths are input thereto, and adjusts an intensity of each optical signal based on an intensity change in a transmission line, and outputs the optical signals. A dummy light output unit (2) outputs dummy lights (D) with different wavelengths, each dummy light having an intensity based on an intensity change in a transmission line. A control unit (4) identifies the dummy light corresponding to each optical signal, and controls the intensity of the identified dummy light based on the intensity of the optical signal corresponding to the identified dummy light and output from the optical signal adjustment unit (1). A multiplexing unit (3) outputs a wavelength-multiplexed optical signal (L) where the dummy light (D) and the optical signal (L10) output from the optical signal adjustment unit are combined.

A system, apparatus, and method for demodulation of a fiber optic sensor is provided. An aspect of the system provides an optical fiber, a laser, a phase modulator configured to be coupled to the optical fiber, and a sensor. The laser emits a laser beam into the optical fiber. The phase modulator receives the laser beam from the laser and directs the laser beam to the sensor. The sensor includes a coiled portion of the optical fiber, uncoiled segments adjacent the coiled portion, and at least two fiber Bragg gratings configured to be coupled to opposite uncoiled segments adjacent the coiled portion of the optical fiber. The sensor system may further include a photodetector configured to receive a reflected portion of the laser beam from the sensor. The reflected portion is divided into at least two paths where at least two sub-outputs are generated for demodulation and sensing.

A system and method for efficient optical signal amplification with system monitoring features are provided. For example, an optical repeater may include two different 4-port thin-film gain flattening filters (TF-GFFs), which may be connected to provide a high-loss loop-back (HLLB) path in the optical repeater for system monitoring. The 4-port TF-GFF may have four different ports and may integrate the functionalities of a conventional GFF and a coupler into a single component, thereby increasing power efficiency of the optical repeater.

An optical multiplexer/demultiplexer according to an example embodiment includes: an OCM configured to measure a strength of each of optical signals in a plurality of wavelength bands input to a WSS and to determine an optical signal wavelength band and a noise wavelength band based on the measured strengths; the OCM configured to pass the optical signal in the optical signal wavelength band determined by the OCM as a primary signal; a dummy light generation unit configured to generate dummy light in which the optical signal wavelength band has been extinguished; and an optical coupler configured to multiplex the primary signal output from the WSS with the dummy signal into a wavelength division multiplexing optical signal and to output the wavelength division multiplexing optical signal to an optical transmission path.

An optical transmission apparatus includes a multiplexing unit multiplexing signal light of a main signal, and dummy lights of odd channel and an even channel emitted using first and second dummy light sources, respectively, a detection unit detecting abnormality of the first and second dummy light sources, and a control unit performing addition control. The addition control includes control in such a way that dummy light of an even channel emitted using the first dummy light source is additionally multiplexed with the signal light, when no abnormality is found in the first dummy light source and an abnormality of the second dummy light source is detected, and that dummy light of an odd channel emitted using the second dummy light source is additionally multiplexed with the signal light, when no abnormality is found in the second dummy light source and an abnormality of the first dummy light source is detected.

Disclosed herein are methods, devices, and systems for providing timing and bandwidth management of ultra-wideband, wireless data channels (including radio frequency and wireless optical data channels). According to one embodiment, a hub apparatus is disclosed for providing out-of-band bandwidth management for a free-space-optical (FSO) data channel associated with a first device. The hub apparatus includes a processor, a memory coupled with the processor, an FSO transmitter coupled with the processor, and an FSO receiver coupled with the processor. The FSO transmitter may be configured to transmit a control signal comprising timing information and bandwidth management information.

Devices, systems and methods for encoding information using optical components are described. An example photonic filtered sampler includes a spectral shaper configured to receive an optical pulse train, a dispersive element positioned to receive an output of the spectral shaper and to expand spectral contents thereof in time, and a modulator configured to receive an output of the dispersive element and a radio frequency (RF) signal, and to produce a modulated output optical signal in accordance with the RF signal. In this configuration, one or more characteristics of the modulated output optical signal is determined based on a spectral shape provided by the spectral shaper and dispersive properties of the dispersive element.

An optical communication system configured with a station-side apparatus and a plurality of subscriber-side apparatuses in a bus network topology includes an optical amplification unit installed on a station side, and a drop unit configured to branch an optical signal and excitation light, wherein the optical amplification unit includes an amplifier configured to amplify a downlink signal, and an excitation light output unit configured to output the excitation light for amplifying an uplink signal to a communication path, and the drop unit changes a branching ratio in accordance with a wavelength of the optical signal so that a transmission loss of the excitation light with respect to a trunk fiber is reduced.

Systems and methods for resolving control conflicts in trunk protection links are provided. A head-end node includes a first line-mux controller and a second line-mux controller, first actuator components for a first fiber span, and second actuator components for a second fiber span, wherein the first line-mux controller and the second line-mux controller are configured to control the first actuator components and the second actuator components, respectively, and a trunk protection switch configured to connect an input to each of the first fiber span and the second fiber span.

Systems and methods for compensating for spectrum power offsets with respect to a target profile are provided. A method, according to one implementation, includes determining whether an upstream controller is currently performing an upstream action, or intends to perform the upstream action soon thereafter, with respect to an upstream power compensation unit. The method also includes determining whether there is a need to perform a local action with respect to the local power compensation unit. Furthermore, the method includes the step of performing the local action with respect to the local power compensation unit in response to determining that (a) the upstream controller is not currently performing the upstream action (or does not intend to perform the upstream action soon thereafter) and (b) there is a need to perform the local action.