An optical transmitter includes a dummy optical source, a polarized wave beam coupler, and an auto gain control (AGC)-system amplifier. The dummy optical source outputs, out of an optical signal in which an optical path signal and an optical packet signal are mixed, a dummy signal having a wavelength identical to that of the optical packet signal. The polarized wave beam coupler multiplexes the dummy signal with the optical signal so that the dummy signal is orthogonal to the optical signal so as to output an output signal. The AGC-system amplifier inputs the output signal, and amplifies the output signal with a predetermined amplification factor corresponding to a power difference between input power and output power of an optical amplifier.

A communication system includes a first optical system and a second optical system optically connected to a clamping laser and a pump laser. The first optical system includes first and second optical splitters. The first optical splitter is configured to receive a clamping laser signal from the clamping laser and split the signal into split clamping laser signals. The second optical splitter is configured to receive a pump laser signal from the pump laser and split signal into split pump laser signals. The second optical system is optically connected to the first optical system and includes amplifier systems. Each amplifier system is configured to receive a multiplexed signal. The second optical system includes first and second combiners optically connected to an erbium-doped fiber. The first combiner is optically connected to the first splitter, and the second combiner is optically connected to the second splitter.

An optical relay device is provided which is capable of outputting control signal light without equipping a light source for the control signal light and capable of flexibly managing and changing a wavelength of the control signal light in accordance with a state of a network. The optical relay device includes an optical receiving unit that receives a wavelength multiplexed optical signal, a control unit that specifies a first wavelength and outputting notification information, and a processing unit that selects an optical signal having the first wavelength from the received wavelength multiplexed optical signal, applying intensity-modulation in accordance with the notification information to the selected optical signal, adding the intensity-modulated optical signal back to the wavelength multiplexed optical signal, and outputting the wavelength multiplexed optical signal.

[Problem] To provide an optical transmission/reception device, an optical communication system, an optical communication method, and a program which are capable of securing the confidentiality of information included in an optical signal even when the optical signal is transferred to a device that is not an original transmission destination device.

[Solution] This optical transmission/reception device is provided with: a wave separation unit for receiving a wavelength-multiplexed optical signal and separating the same into a plurality of optical signals; a plurality of reception units for receiving each of the plurality of optical signals separated by the wave separation unit; a plurality of output units for outputting optical signals differing in wavelength from each other; a control unit for requesting, in response to the inclusion in the received wavelength-multiplexed optical signal of an optical signal to which a prescribed process has been applied, that a prescribed change be applied to the optical signal outputted by at least one of the plurality of output units; and a wave combining unit for combining the plurality of optical signals outputted from the plurality of output units and outputting the combined signal.

An optical transmission system includes: a reception apparatus configured to receive signal light separated from wavelength division multiplexing light; and a management apparatus configured to manage a plurality of optical transmission apparatuses that transmit the wavelength division multiplexing light, wherein the reception apparatus further comprises: an amplification section configured to amplify each power of electric signals for demodulating the signal light within a predetermined tolerance level, the electric signals being converted from mixed light of local light and the signal light input into the reception apparatus; an adjustment section configured to adjust power of the signal light input into the reception apparatus or power of the local light; and a controller configured to control the adjustment section based on an adjustment amount notified by the management apparatus, the management apparatus includes a computer.

A communication system includes a first optical system and a second optical system optically connected to a clamping laser and a pump laser. The first optical system includes first and second optical splitters. The first optical splitter is configured to receive a clamping laser signal from the clamping laser and split the signal into split clamping laser signals. The second optical splitter is configured to receive a pump laser signal from the pump laser and split signal into split pump laser signals. The second optical system is optically connected to the first optical system and includes amplifier systems. Each amplifier system is configured to receive a multiplexed signal. The second optical system includes first and second combiners optically connected to an erbium-doped fiber. The first combiner is optically connected to the first splitter, and the second combiner is optically connected to the second splitter.

Methods and systems for current amplification to improve optical amplifier performance may include equalizing a current level indicative of input optical power to an optical amplifier with a current level indicative of an output optical power level of the optical amplifier. In this manner, a first bandwidth of an input log amp may be matched with a second bandwidth of an output log amp in a gain control loop circuit to improve overall transient gain accuracy of the optical amplifier, irrespective of the input optical power. In this manner, the optical amplifier may be enabled to operate at a defined gain level even in the presence of transients in the input signal.

A transmission loss measurement device includes: a first monitor configured to measure a first optical power of a specific wavelength among wavelength-multiplexed light amplified by a Raman amplifier according to a power of pump light, the wavelength-multiplexed light being transmitted to an optical transmission line; a second monitor configured to measure a second optical power of the specific wavelength among the wavelength-multiplexed light received from the optical transmission line; a storage device configured to store a procedure for calculate a transmission line loss; and a processor configured to execute the procedure by: calculating a gain by the Raman amplifier, based on the power of the pump light; calculating the transmission line loss based on the first optical power, the second optical power, and the gain by the Raman amplifier; and correcting the transmission line loss according to a change of a number of wavelengths of the wavelength-multiplexed light.

An optical transmitter includes an amplifying unit, a monitor, an identifying unit, and a controlling unit. The amplifying unit amplifies an optical signal in which an optical packet signal is mixed in optical path signals. The monitor monitors power of the optical signal on an input stage and an output stage of the optical amplifying unit, respectively. The identifying unit identifies an optical packet signal section on the input stage side based on the monitoring result on the input stage side, and identifies an optical packet signal section on the output stage side based on the monitoring result on the output stage side. The controlling unit compares the power of the identified section on the input stage side with the power of the identified section on the output stage side, and controls an amplification factor of the amplifying unit based on a power difference resulting from the comparison.

An optical transmitter includes an amplifying unit, a monitor, an identifying unit, and a controlling unit. The amplifying unit amplifies an optical signal in which an optical packet signal is mixed in optical path signals. The monitor monitors power of the optical signal on an input stage and an output stage of the optical amplifying unit, respectively. The identifying unit identifies an optical packet signal section on the input stage side based on the monitoring result on the input stage side, and identifies an optical packet signal section on the output stage side based on the monitoring result on the output stage side. The controlling unit compares the power of the identified section on the input stage side with the power of the identified section on the output stage side, and controls an amplification factor of the amplifying unit based on a power difference resulting from the comparison.