Fujitsu Corporation

Fujitsu Telecom Networks Limited

Shingo Hara

Toshihiro Suzuki

Miwa Taniguchi

Kazuaki Nagamine

Eiji Iida

Tomoyuki Kanzaki

Masahiro Yuki

Takeshi Sakamoto

Takuma Shouji

Takeshi Hoshida

Tomoaki Takeyama

Kosuke Komaki

Shota Mori

Manabu Suzuki

Hideaki Sugiya

Tomohiro Yamauchi

Kazutaka Kikuta

Tomoko Murakami

Hiroki Satou

Kouji Kawakami

A device includes a first excitation light source that emits first excitation light, a second excitation light source that emits second excitation light, a wavelength converter that converts signal light of a first wavelength into signal light of a second wavelength according to the first excitation light, and a measurer that measures a frequency difference between the first excitation light and the second excitation light, wherein when an abnormality of the first excitation light is detected, the second excitation light source is adjusted so that a frequency of the second excitation light is aligned with a frequency of the first excitation light before the abnormality detection, based on the frequency difference before the abnormality detection, and the wavelength converter converts the signal light of the first wavelength into the signal light of the second wavelength according to the second excitation light, after adjusting the frequency of the second excitation light.

Wavelength conversion device and excitation light switching method

A transmission device, includes a first wavelength converter configured to convert a second wavelength-multiplexed signal in a first wavelength band to a second wavelength band different from the first wavelength band, and a multiplexer configured to transmit, after the conversion, a wavelength-multiplexed signal obtained through multiplexing of a first wavelength-multiplexed signal in the first wavelength band, a first supervisory control signal light ray that is a control signal for the first wavelength-multiplexed signal, the second wavelength-multiplexed signal in the second wavelength band, and a second supervisory control signal light ray that is a control signal for the second wavelength-multiplexed signal, wherein the first supervisory control signal light ray and the second supervisory control signal light ray each have a wavelength in a wavelength band different from the first wavelength band and the second wavelength band.

Transmission system, transmission device, and transmission method

A transmission device transmits a frame to a correspondent device and receives a frame from the correspondent device. The transmission device includes: a measurement unit configured to perform a delay measurement that measures a period of time from when a frame is transmitted to the correspondent device until when a corresponding frame is received from the correspondent device; and a delay decision unit configured to determine a transmission delay between the transmission device and the correspondent device based on a plurality of target measurement results obtained from a plurality of delay measurements except for at least a first delay measurement among delay measurements performed by the measurement unit.

Transmission device and method for measuring delay

In an apparatus having data installed therein, the apparatus includes a data storage part for storing a (n+1)th-order file obtained by bundling an nth-order file and (n+1)th data corresponding to an (n+1)th function level into one file, wherein n is an integer, an identifier storage part for storing an identifier indicating a function level of data to be installed in the apparatus, and a controller for detecting the function level based on the identifier stored in the identifier storage part, de-bundling the (n+1)th-order file stored in the data storage unit as many as times corresponding to the function level, and applying the de-bundled data to the apparatus.

Apparatus having data installed and method of upgrading data

Raman amplifier includes: a pump-light generator configured to supply pump light to a transmission fiber; a measurement circuit configured to measure a relationship between power of the pump light and power of noise output from the transmission fiber with respect to a range from first pump-light power to second pump-light power; a signal detector configured to monitor a supervisory signal in output light of the transmission optical; and a decision unit configured to decide a state of the transmission fiber according to the monitoring result. When the supervisory signal is detected without the pump light, the measurement circuit measures the relationship while increasing the power of the pump light from the first pump-light power. When the supervisory signal is not detected without the pump light, the measurement circuit measures the relationship while decreasing the power of the pump light from the second pump-light power.

Raman amplifier

To provide a transmission apparatus capable of setting the same control data to the entire child transmission apparatuses instantaneously at a time, thereby leading to improved maintenance operation and bringing about efficient maintenance and system stability. The transmission apparatus receives from a maintenance operator a designation of a parent apparatus having the control data set in advance. That control data is to be inherited to a child apparatus. The transmission apparatus determines whether any transmission apparatus has already been registered as parent apparatus in the child apparatus, and also determines whether the designated parent apparatus has already been registered as a child apparatus in the child apparatus. The transmission apparatus then requests the designated parent apparatus to transfer the control data in the designated parent apparatus to the child apparatus, when the designated parent apparatus is not registered in the child apparatus.

Inheritance control method of network control data between transmission apparatuses and transmission apparatus using the same

Gain setting of a receiving amplifier, is performed by detecting the necessity of gain setting when a receiving amplifier is turned on, requesting WDM transmission equipment in a preceding station to output ASE light; in a WDM transmission equipment of the preceding station, shutting off both passing-through light and added light, and outputting the ASE light corresponding to a predetermined number of wavelengths of signal light; in the receiving amplifier of the WDM transmission equipment in the station of interest, performing the gain setting by use of the ASE light; and on completion of the gain setting, the WDM transmission equipment of the station of interest, requesting the WDM transmission eouipment of the preceding station to halt the ASE light output, and the WDM transmission equipment of the preceding station, halting the ASE light output upon receiving the request and switching the output to an optical signal output.

Gain setting method in wavelength division multiplex transmission equipment

When a tunable laser is operating at any one of the different wavelengths, wavelength data is sampled and stored in a memory device. In the case where the same operating wavelength as a wavelength hitherto operated needs to be reset to the tunable laser, the wavelength data stored in the memory device is set to the tunable laser. This makes it possible to avoid a shift in wavelength due to age degradation of the tunable laser that selectively outputs any one of light signals of different wavelengths in dependence on the wavelength data set to the tunable laser.

Method and unit for setting a wavelength to a tunable laser

For a WDM device including a multiplexer receiving fixed wavelengths, wavelength-converting parts for converting input wavelengths from optical transmission devices into the fixed wavelengths, and interface parts provided between the multiplexer and the wavelength-converting parts and having a specific wavelength that matches the fixed wavelength of the multiplexing part, a method and a device is provided for automatically determining the specific wavelength of the interface part that is to be selected as a converted wavelength output from the wavelength-converting part.

Growing community of inventors

Kawasaki, Japan

Shingo Hara