Fujitsu Corporation

Keisuke Harada

Setsuo Yoshida

Yutaka Kai

Taku Yoshida

Susumu Kinoshita

George Ishikawa

Shoichiro Oda

Goji Nakagawa

Kyosuke Sone

Yoshiyuki Maeda

Hiroshi Oikawa

Yoshitaka Eguchi

Satoru Miyazaki

An optical signal-to-noise ratio (OSNR) measuring device includes a processor, wherein the processor executes a process. The process includes: converting an optical signal to an electrical signal; first acquiring a signal intensity from the electrical signal; second acquiring a noise intensity of a predetermined frequency band from the electrical signal; performing a digital conversion on the noise intensity; and computing an OSNR of the optical signal based on the signal intensity and the converted noise intensity. The predetermined frequency band is a frequency band including a folding noise that occurs when the digital conversion is performed.

Optical signal-to-noise ratio measuring device and optical signal-to-noise ratio measuring method

An optical level control apparatus includes an input port, an output port, an optical device to assume a state of outputting light inputted to the input port from the output port and a state of not outputting the light inputted to the input port from the output port; a detector to detect an intensity of the light inputted to the input port, and a control unit to detect an input of an optical burst signal to the input port on the basis of a result of detecting the intensity of the light and to control the optical device so that the signal, in which to eliminate a field extending up to an elapse of a period of first time equal to or shorter than laser ON time period of the signal from a head of the signal with its input being detected, is output from the output port.

Optical level control apparatus and optical reception apparatus

An optical amplification apparatus includes a front-stage semiconductor optical amplifier which amplifies an input light and a rear-stage semiconductor optical amplifier which amplifies an amplified light outputted from the front-stage semiconductor optical amplifier. The front-stage semiconductor optical amplifier exercises auto level control of an output light by exercising variable control of driving current which flows according to applied voltage higher than light emitting threshold voltage of an internal optical amplification element. The rear-stage semiconductor optical amplifier performs gate switching of a transmitted light by exercising switching control of driving current. By doing so, distortion of a waveform is controlled and optical communication quality can be improved.

Optical amplification apparatus

A level control circuit that generates output signal for level control includes: a control information storage that stores control information corresponding to a signal level, a control information circuit that outputs the output signal for level control corresponding to the signal level of a first input signal based on the control information stored in the control information storage; and an information update circuit that updates the control information of the control information storage according to the signal level of a second input signal.

Level control circuit, level control method, and level control system

An optical output level control apparatus includes a detector configured to detect power of an input optical signal; an amplifier configured to amplify the input optical signal; a memory configured to store data that define a first curved line representing a relationship between the input power and a drive voltage of the amplifier for obtaining a first output level and data that defines a second curved line representing a relationship between the input power and the drive voltage of the amplifier for obtaining a second output level; a generator configured to correct at least one of the first and second curved lines and generate a target curved line representing a relationship between input power and a drive voltage of the amplifier for obtaining a target output level through interpolation based on the first and second curved lines at least one of which is corrected.

Optical output level control apparatus

An optical communication apparatus includes an optical signal transmitter for outputting an optical signal, an optical switch device for switching a route of the optical signal, a drive controller for supplying a drive current for controlling a route switching to the optical switch device, a cooling device for cooling the optical switch device on the basis of a control signal, a temperature controller for transmitting the control signal to the cooling device in order to keep a measured temperature at a specific temperature, where the measured temperature is related to a temperature of the optical switch device.

Optical communication apparatus, control apparatus, and method for controlling optical output

An optical packet switching apparatus includes plural optical switches, an optical switching section that switches a path of an optical packet transmitted thereto according to the switch control signal to output the optical packet, and a control section that takes out a header portion representing a destination of the optical packet transmitted, photoelectrically converts the header to generate the switch control signal according to the destination to transmit the switch control signal to the optical switching section and controls the optical switch. The apparatus further includes a light monitor section that monitors a light quantity level of the optical packet transmitted and a light quantity level of the optical packet to be sent out, and an abnormality recognizing section that recognizes an effective timing of monitoring of the light quantity levels based on the switching control signal, and recognizes an abnormality based on the light quantity levels at the timing.

Optical packet switching apparatus

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.

Growing community of inventors

Fukuoka, Japan

Keisuke Harada