Fujitsu Corporation

Haruki Tanaka

Hideaki Sugiya

Tomoyuki Sakata

Hisayuki Ojima

Tatsuo Nagayoshi

Takeshi Noma

Yoshikazu Nakanishi

Akira Yamamoto

Toshihiro Suzuki

Daisuke Kobayashi

Hiroaki Tomofuji

Ichiro Nakajima

Takuji Maeda

Taro Asao

Makoto Ohtou

Kouichi Maeda

Akihiro Mukai

Mamoru Suematsu

Yuki Murakami

Yuichi Toyota

Koji Batou

An optical transmission apparatus includes: a wavelength selecting switch, including an input port and an output port having more ports than the input port, configured to perform an adjustment of a level of an optical signal from the input port to the output port; a first monitor configured to monitor the level of the optical signal at the input port unit; a second monitor configured to monitor the level of the optical signal at the output port unit; and a controller configured to control the wavelength selecting switch wherein the controller: calculates a virtual output value for the output port unit based on a first monitor result from the first monitoring unit, a second monitor result from the second monitoring unit, and a current adjustment value for the adjustment function; calculates a new adjustment value based on the virtual output value; and sets the new adjustment value to the adjustment.

Optical transmission apparatus and level adjusting method

Even during a protection period in which a state transition is not caused from an ALC state to an ALD state, when an output light level that is inputted is below a threshold for ALC transition read from a memory, a processor causes a transition by switching an internal state from an ALC state to an ALD state. Then, an ALD operation is started, outputting a control voltage to a VAT control unit so as to achieve a predetermined fixed attenuation amount.

Optical transmitting apparatus and optical multiplexing unit

A transponder includes a CDR section that extracts clocks from an input signal, an oscillating section that can output various frequencies to the CDR section, a frequency instruction processing section that instructs the oscillating section to output an arbitrary frequency, a detection processing section, and a frame processing section control section. The detection processing section determines whether the frequency output from the oscillating section and an input signal synchronize in frequency or not in response to an instruction by the frequency instruction processing section, and detects a synchronization frequency. The frame processing section control section operates a frame processing section based on the synchronization frequency detected by the detection processing section.

Transponder unit, transponder unit control apparatus, transponder unit control method and recording medium recording transponder unit control program

The present invention provides an optical add/drop multiplexer including an optical power control unit for performing a control of an optical power by the unit of each signal light included in the wavelength multiplexed light, wherein the optical power control unit includes control logic for implementing a first control mode in which a transition to an automatic control of the optical power and release from the aforementioned control are carried out by comparing the optical power with a threshold value, and a second control mode in which a transition to an automatic control of the optical power is carried out based on control information of a notification by another of the optical add/drop multiplexers and release from the automatic control is carried out based on the comparison between the optical power and the threshold value.

Optical add/drop multiplexer, control method therefor and control program therefor

An optical-level control apparatus includes a plurality of variable optical attenuators each used for attenuating an input optical signal included in a wavelength division multiplexing signal as a component having a specific wavelength by applying a variable attenuation quantity, a plurality of control units each used for executing automatic control for automatically controlling the attenuation quantity in order to adjust the optical level of an optical signal output by a corresponding one of the variable optical attenuators to a target level in an ordinary normal state of the input optical signal, and a detection unit for detecting a loss of light failure of an optical signal input to each of the variable optical attenuators and detecting disappearance of the loss of light failure. When the detection unit detects the loss of light failure, a corresponding one of the control units executes first attenuation quantity locking control to adjust the attenuation quantity to a first predetermined value and as the detection unit detects the disappearance of the loss of light, the corresponding control unit executes second attenuation quantity locking control to adjust the attenuation quantity to a second predetermined value.

Optical-level control method, optical-level control apparatus and wavelength-multiplexing optical network

An optical transmission system is provided which is capable of booting the system by using an ASE (Amplified Spontaneous Emission) light in a manner to provide high quality. A pre-amplifier receives noise light and does gain setting in an amplifier booting mode and receives an optical signal and to amplify the received signal in a working mode. A variable dispersion compensator is placed in a preceding-stage of the pre-amplifier and makes compensation of dispersion of a wavelength occurring when an optical signal propagates through an optical fiber in a variable manner. A switching unit to select, when the noise light passes through the variable dispersion compensator, if a level of the noise light is deviated from a desired level, a bypass route so as to make the noise light not be input to the variable dispersion compensator but be input to the pre-amplifier in an amplifier booting mode according to a switching instruction and to select a passage route so as to make the optical signal, after having been input to the variable dispersion compensator and having undergone dispersion compensation, be input to the pre-amplifier according to the switching instruction in a working mode.

Optical transmission system

Growing community of inventors

Fukuoka, Japan

Haruki Tanaka