Techniques are described for determining, with a first optical node, a correction factor indicative of an amount of optical power loss that a Raman amplifier in a second optical node causes in an optical signal having a first wavelength that is transmitted by the first optical node and received by the second optical node, transmitting, with the first optical node to the second optical node, information, based on the determined correction factor, that is to be used for determining a gain of the Raman amplifier, and transmitting, with the first optical node to the second optical node, an optical signal having a second wavelength that is to be amplified by the Raman amplifier.

An optical communication link that includes two nodes interconnected by an optical channel that comprises optical fiber(s), and that is used to communicate an optical signal comprising multiple optical signal wavelengths. The first node provides an optical signal onto the optical channel towards the second node, or receives an optical signal from the optical channel from the second node. A Raman pump provides Raman pump power into the optical fiber of the optical channel to thereby perform Raman amplification of the optical signal in the optical fiber. The second node determines a quality measurement of at least of optical wavelength signals transmitted by the first node to the second node. The second node also transmits information from the quality measurement back to the first node. A controller at the first node controls at least one parameter of the Raman pump in response to this transmitted information.

A Raman pumping arrangement for amplifying a data optical signal (40) has a Raman pump (12) for generating a Raman pump signal (44;45), an optical supervisory channel receiver (14) for receiving an optical supervisory channel signal (42) an amplification fiber (15) arranged such that the data optical signal (40), the optical supervisory channel signal (42), and the Raman pump signal (44;45) are transmitted therethrough; and a control unit (13) configured for controlling the operation of the Raman pump (12); wherein the control unit (13) is configured for setting the Raman pump (12) in an operation mode or a start-up mode; wherein in the operation mode, the Raman pump (12) provides an operation pumping power (120), and wherein in the start-up mode, the Raman pump (12) provides a start-up pumping power (122).

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.

A submarine optical repeater includes a submarine amplifier module, which further includes a pumping laser module and an optical detector module. The pumping laser module generates optical amplifications within an optical cable, and, in the case of a fault in the optical cable, the optical detector module detects at least one characteristic of an optical signal caused by the fault in the optical cable. This configuration then identifies a particular signal characteristic that indicates a fault within the optical cable.

An optical transmission line monitoring device is one of two facing optical transmission line monitoring devices connected by an optical transmission line via a relay, and includes a transmission unit that transmits an own-device monitoring signal to the optical transmission line, a reception unit that receives a monitoring signal, a mixture of a turnback monitoring signal, which is the own-device monitoring signal turned back, and an other-device monitoring signal, having a pulse width and amplitude different from the own-device monitoring signal and transmitted from the facing optical transmission line monitoring device, an identification unit that identifies the turnback and other-device monitoring signals in the monitoring signal, using identification criteria for identifying the turnback and other-device monitoring signals from the monitoring signal, and an output unit that outputs an identification result for the turnback and other-device monitoring signals. Therefore, the optical transmission line is reliably monitored using opposing bidirectional monitoring signals.

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 light measurement step.

A Raman amplification device that Raman-amplifies an optical signal in a transmission line by Raman pumping, the Raman amplification device includes a processor configured to monitor a first signal communicated by the optical signal, set a threshold level of an alarm (WDMLOS) detection for determining whether the alarm is output at a time of transmission line disconnection in accordance with a monitoring result of the first signal, determine whether auto power shut down (APSD) control is performed by using a first APSD determination condition based on integration of optical supervisory channel (OSC) disconnection and the alarm, in a case where the monitoring result of the communicated first signal exceeds a predetermined condition, and determine whether the APSD control is performed by using a second APSD determination condition based on the OSC disconnection, in a case where the monitoring result of the communicated first signal is lower than the predetermined condition.

An optical network unit (ONU) includes an optical transceiver module, a switch, a detecting module, and an ONU chip. The switch is electronically coupled between the optical transceiver module and a power supply. The detecting module is electronically coupled between the switch and the power supply. The detecting module includes a sensor, an amplifier, and a comparator. The sensor is electronically coupled between the power supply and the switch to sense a driving current output from the power supply to the optical transceiver module and output a voltage signal to the amplifier, the amplifier amplifies the voltage signal and outputs an amplified voltage signal to the comparator, the comparator compares the amplified voltage signal with a predetermined voltage signal and outputs a comparison result. The ONU chip controls the switch to connect/disconnect the electrical connection between the optical transceiver module and the power supply according to the comparison result.

A communications device is disclosed and includes: a first acquiring unit for acquiring first specific wavelength light and second specific wavelength light from a first optical path; a first receiving unit for converting the first specific wavelength light coming from the first acquiring unit into a first electrical signal; a first control unit for sending a first modulating signal to a first loopback unit according to the first electrical signal coming from the first receiving unit; and the first loopback unit for modulating the second specific wavelength light coming from the first acquiring unit according to the first modulating signal, and looping the modulated second specific wavelength light back to a second optical path, where a transmission direction of an optical signal in the second optical path is opposite to a transmission direction of an optical signal in the first optical path. The present invention further discloses a communications method.