Abstract: A wavelength-selective optical reception device includes a photoreceptor (21) that converts optical signals (201) into electric signals and outputs the electric signals, a base (31) on which the photoreceptor (21) is provided, a housing (41) that is mounted on the base (31) and surrounds the photoreceptor (21) along with the base (31), and that is provided with a window (51) to pass optical signals (203) including the optical signals (201) and including optical signals (202) of a wavelength different from a first wavelength of the optical signals (201) and a window (52) to pass the optical signals (202), and an optical filter (61) that is disposed inside the housing between the window (51) and the photoreceptor (21) along the optical axis (205) of the optical signals (203), and that outputs, out of the optical signals (203) that enter thereto, the optical signals (201) toward the photoreceptor (21), and reflects the optical signals (202) toward a near side in a direction of travel of the optical signals (203)

Abstract: A coherent optical reception device includes a coherent receiver that receives signal light in which an AMCC signal is superimposed on a main signal by phase modulation and outputs a reception signal and a digital signal processor, in which a modulation signal of the AMCC signal superimposed on the main signal is multiplied by a clock, the digital signal processor includes a symbol output, an AMCC signal code sequence demodulator, and a main signal code sequence demodulator, and the AMCC signal code sequence demodulator includes a main signal component remover that removes the main signal included in the reception signal output from the symbol output, and a clock component remover that removes a clock component included in the reception signal from which the main signal has been removed by the main signal component remover.

Abstract: An optical reception device including: a local light transmission unit configured to generate a plurality of local lights having different wavelengths, select a local light having a wavelength that is close to the wavelength of a received optical signal from among the plurality of generated local lights having different wavelengths, and transmit the selected local light to a coherent receiver; a demultiplexing unit configured to demultiplex a received optical signal and transmit the demultiplexed optical signal to the coherent receiver via a first path; and a wavelength detection unit configured to input the optical signal demultiplexed by the demultiplexing unit via a second path, split the input optical signal into different paths according to wavelengths by using a wavelength multiplexer/demultiplexer, and output, to the local light transmission unit, a control signal for causing the local light transmission unit to output a local light having a frequency that corresponds to a path in which the optical sig

Abstract: 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.

Abstract: A station-side telescope included in a station-side optical antenna unit is configured to transmit and receive an optical signal, a guide light source is configured to emit guide light in a direction of orientation of the station-side telescope, a node-side telescope is configured to transmit and receive an optical signal, a node-side control unit included in a node-side optical antenna unit is configured to generate and output a control signal for moving a node-side base based on a position of the guide light included in an image obtained by a camera capturing the guide light emitted by the guide light source so that a direction of orientation of the node-side telescope faces the direction of orientation of the station-side telescope, an antenna drive unit is configured to receive the control signal and generate and output a drive signal based on the control signal, and the node-side base included in the node-side optical antenna unit is configured to support the node-side telescope and receive the drive sig

Abstract: An optical communication system includes: an optical fiber including a plurality of cores formed in parallel to a longitudinal direction; a first optical communication device including an optical transmission unit and an optical reception unit, and provided with connection ends of the optical transmission unit and the optical reception unit each connected to one end of any one of the cores on an interface surface; and a second optical communication device including an optical transmission unit and an optical reception unit, and provided with connection ends of the optical transmission unit and the optical reception unit each connected to another end of any one of the cores on an interface surface, in which the connection ends are provided in an arrangement in which a type of transmission and reception of one of the connection ends of the first optical communication device and a type of transmission and reception of one of the connection ends of the second optical communication device are a transmission and re

Abstract: A coherent optical reception device includes a coherent receiver that receives signal light in which an AMCC signal is superimposed on a main signal, converts the signal light into an analog electric signal, and outputs an in-phase component and a quadrature-phase component of a reception signal for each polarization state, and a polarization combiner that performs polarization combining on the in-phase component and the quadrature-phase component of the reception signal output from the coherent receiver for each polarization state and outputs the reception signal as an AMCC signal identification reception signal that is the reception signal used for identification of the AMCC signal and a main signal identification reception signal that is the reception signal used for identification of the main signal.

Abstract: An optical transmitting device includes a plurality of optical transmitting units that output optical signals with different wavelengths, a multiplexer that wavelength-multiplexes the plurality of the optical signals output from the plurality of optical transmitting units, and an amplifying unit that amplifies the wavelength-multiplexed optical signal, in which the plurality of optical transmitting units include a monitoring control signal application unit that adds a monitoring control signal to a constant current for driving a laser to generate a driving signal and applies the driving signal to the laser, a laser that outputs an optical signal in accordance with the driving signal applied to the monitoring control signal application unit, and a modulator that modulates the optical signal output from the laser with a main signal.

Abstract: There is provided an optical power feeding system including: an optical power feeding unit; and a plurality of drop units configured to be able to receive light from the optical power feeding unit as an input, branch the input light, and output branched light, in which, the optical power feeding unit includes a power-feed light generating unit that outputs power-feed light, and the drop unit includes: an optical splitter that branches the power-feed light into first branch light and second branch light and outputs the second branch light to another drop unit; a photoelectric conversion unit that performs photoelectric conversion of the first branch light; and a branch ratio control unit that is driven by electricity generated by the photoelectric conversion and controls a branch ratio that is a ratio between the first branch light and the second branch light.

Abstract: The optical communication system includes the optical distribution device (100) provided between the wavelength routing device (30) and the optical multiplexing/demultiplexing device (40). The wavelength routing device outputs the optical signal input from the port on the wavelength variable subscriber device side to the port uniquely determined by a combination of the wavelength of the optical signal and the port to which the optical signal is inputted. The wavelength variable subscriber device can execute the first protection for switching the wavelength of the optical signal to be transmitted and received to the spare wavelength different from the operating wavelength when the wavelength variable subscriber device and the wavelength variable communication device (10) are disconnected.

Abstract: A branch ratio setting system includes: a branch ratio control unit; and a plurality of drop units configured to be able to receive an optical signal from the branch ratio control unit, and configured to branch and output the received optical signal, and the branch ratio control unit outputs light to the plurality of drop units via an optical fiber to measure characteristics of the optical fiber, and outputs a branch ratio determination signal to each of the plurality of drop units via the optical fiber based on the measured characteristics of the optical fiber, and the drop unit includes an optical splitter connected to the optical fiber and having a variable branch ratio and a branch ratio setting unit that sets the branch ratio of the optical splitter based on the branch ratio determination signal input via the optical fiber.

Abstract: An optical amplification estimation method includes by an excitation light output unit connected to a first end of a first optical transmission line, making excitation light incident on the first optical transmission line, by a monitoring unit connected to the same side as the first end of the first optical transmission line, making monitoring light incident on the first optical transmission line, the monitoring light having a wavelength different from a wavelength of the excitation light, by the monitoring unit, measuring intensity of light incident on the monitoring unit when the excitation light is incident, and intensity of light incident on the monitoring unit when the excitation light is not incident, and by an amplification estimation unit, estimating a gain of an optical signal in the first optical transmission line based on the light intensity measured in the measuring.

Abstract: A light leakage confirmation method comprising: an excitation light incident step in which an excitation light output unit connected to a first end of a first optical transmission line outputs an excitation light and makes the excitation light incident on the first optical transmission line; a reflection step in which an excitation light reflection unit connected to a second end of the first optical transmission line reflects the excitation light which has been incident in the excitation light incident step; a reflected light incident step of making a reflected light which has been reflected in the reflection step incident on the first optical transmission line; a reflected light measurement step in which the excitation light output unit measures an intensity of the reflected light; and a leakage determination step of determining whether or not the excitation light is leaked on a basis of the intensity of the excitation light and the intensity of the reflected light which has been measured in the reflected li

Abstract: An aspect of the present disclosure is a transmission system including a modulated wave generation unit that generates an intermediate wave, which is a coherent wave in which a frequency component of either of two signals overlays a frequency spectrum, the two signals being a main signal indicating transmitted information to be transmitted and a control signal indicating management information, which is information on communication between a transmission source of the transmitted information and a communication destination of the transmission source, and a modulation unit that modulates the intermediate wave with a signal in which a frequency component does not overlay the frequency spectrum of the coherent wave generated by the modulated wave generation unit out of the two signals that are the main signal and the control signal. In the transmission system, a frequency band of the main signal and a frequency band of the control signal do not overlap each other.

Abstract: An optical reception device including: a wavelength selection unit configured to split an optical signal amplified by an optical amplifier into different paths according to wavelengths by using a wavelength multiplexer/demultiplexer, and control a passage state of a passage target optical switch through which the optical signal is to be passed, out of a plurality of optical switches provided on the respective paths, to select an optical signal of a path where the optical signal entered and output the optical signal to a receiver; and a wavelength detection unit configured to detect the wavelength of an optical signal by using each of a plurality of optical detectors, determine the passage target optical switch based on a detection result, and output, to the determined passage target optical switch, a control signal for controlling the passage target optical switch so as to enter the passage state, the optical detectors being respectively provided on different paths that are different from the paths on which t

Abstract: An optical communication system having an optical transmission line, where a first section of the optical transmission line is connected to a first optical communication device; and a second section of the optical transmission line is connected to a second optical communication device. The optical communication system further includes: a Raman light source; an incident device connected to same end of the second section of the optical transmission line as the second optical communication device; and a separating device interconnecting the first section of the optical transmission line to the second section of the optical transmission line. The incident device causes excitation light output from the Raman light source to be incident to the second section of the optical transmission line and performs distributed Raman amplification on the optical signal; and the separating device separates the excitation light that is caused to be incident by the incident device.

Abstract: An optical communication apparatus includes an optical switch, a wavelength management control unit, and an optical switch control unit. The optical switch is connected to a plurality of transmission lines and outputs an optical signal input from one of the transmission lines to another of the transmission lines. The wavelength management control unit assigns a wavelength to a subscriber terminal according to a communication destination. The optical switch control unit controls the optical switch such that it outputs an optical signal transmitted from the subscriber terminal, to which a wavelength has been assigned, to a transmission line corresponding to its forwarding destination on a path to the communication destination.

Abstract: An optical wavelength selecting filter-module into which light is incident from a prescribed direction determined in advance, the optical wavelength-selective filter module including: an optical filter of which an orientation can be changed; a frequency information acquiring unit which acquires frequency information that is information indicating a frequency of light to be transmitted through the optical filter; a temperature information acquiring unit which acquires temperature information that indicates a temperature of the optical filter; a determining unit which determines an orientation of the optical filter based on relationship information that is information associating, for each prescribed frequency, the temperature and an orientation of the optical filter at which light of the frequency is transmitted through the optical filter at transmittance equal to or higher than prescribed transmittance at the temperature, a temperature indicated by the temperature information, and a frequency indicated by the

Abstract: An optical reception device including: a wavelength selection unit configured to split an optical signal amplified by an optical amplifier into different paths according to wavelengths by using a wavelength multiplexer/demultiplexer, and control a passage state of a passage target optical switch through which the optical signal is to be passed, out of a plurality of optical switches provided on the respective paths, to select an optical signal of a path where the optical signal entered and output the optical signal to a receiver; and a wavelength detection unit configured to detect the wavelength of an optical signal by using each of a plurality of optical detectors, determine the passage target optical switch based on a detection result, and output, to the determined passage target optical switch, a control signal for controlling the passage target optical switch so as to enter the passage state, the optical detectors being respectively provided on different paths that are different from the paths on which t

Abstract: An optical reception device including: a local light transmission unit configured to generate a plurality of local lights having different wavelengths, select a local light having a wavelength that is close to the wavelength of a received optical signal from among the plurality of generated local lights having different wavelengths, and transmit the selected local light to a coherent receiver; a demultiplexing unit configured to demultiplex a received optical signal and transmit the demultiplexed optical signal to the coherent receiver via a first path; and a wavelength detection unit configured to input the optical signal demultiplexed by the demultiplexing unit via a second path, split the input optical signal into different paths according to wavelengths by using a wavelength multiplexer/demultiplexer, and output, to the local light transmission unit, a control signal for causing the local light transmission unit to output a local light having a frequency that corresponds to a path in which the optical sig