Fujitsu Corporation

Satoru Miyazaki

Taku Saito

Yoshitaka Taki

Hirofumi Araki

Keisuke Harada

Hiroshi Oikawa

Yoshitaka Eguchi

Kazuya Amaki

An optical transmission system includes: a transmission node to transmit wavelength-multiplexed light of a plural wavelengths arranged in a predetermined transmission band; and a reception node to receive the wavelength-multiplexed light, and to include a monitor to monitor a detection sensitivity indicating a sampling phase shift with respect to a phase of light corresponding to one among the received plural wavelengths, and a transmitter to transmit information indicating that the monitored detection sensitivity for light corresponding to a wavelength adjacent to an outer edge of the transmission band, among the plural wavelengths, has been reduced below a threshold value, to the transmission node, wherein the transmission node includes a receiver to receive information indicating a reduction in the detection sensitivity, and a controller to stop wavelength control of shifting the wavelength adjacent to the outer edge in a direction approaching the outer edge in response to reception of the information.

Optical transmission system, wavelength control method and node

An optical amplifier to which an optical output power automatic attenuation circuit according to the present invention is applied, comprises: one amplifier board to and from which a WDM light is input and output; and a plurality of booster boards which supply pumping lights to the amplifier board, an ID pattern generated in an ID pattern generating circuit disposed in each of the booster boards is superposed on the pumping light to be sent to the amplifier board, an electric signal indicating a monitoring result of the pumping light in a light receiver disposed on the amplifier board is transmitted to each of the booster boards, it is detected in an ID coincidence detection circuit in each of the booster boards whether or not a received ID pattern contained in the electric signal is coincident with the generated ID pattern, and a connection condition of an output fiber is judged according to the detection result so that an output level of the pumping light is controlled. Thus, it is possible to detect with a simple configuration the erroneous connection of an optical fiber between each of a plurality of transmission sections and a reception section, thereby reliably preventing the light of high power from being emitted to the outside.

Optical output power automatic attenuation circuit for optical communication apparatus

In a light amplifier device having a rare-earth element doped optical fiber to which an input light signal and an exciting light are applied, an exciting-light emitting part generates the exciting light. A variable attenuator which attenuates the exciting light applied. A driving part which supplies a driving current to the exciting light part. A monitor part monitors the input light signal. A light-emitting part generates a light in a wavelength band which includes a wavelength of the input light signal. A control part for controlling either the attenuator or driving part, when the monitor part detects a change in the input light signal, so that the light generated by the light-emitting part is applied to the rare-earth element doped optical fiber.

Light amplifier device capable of suppressing light surge

Growing community of inventors

Setagaya, Japan

Satoru Miyazaki