Fujitsu Corporation

Taro Asao

Kazuo Tanaka

Nobuyuki Nemoto

Kazunori Horachi

Akira Yamamoto

Tatsuo Nagayoshi

Miwa Taniguchi

Toshihiro Suzuki

Seiichi Kobayashi

Takuji Maeda

Manabu Suzuki

Takayuki Shimizu

Yuji Shimada

Masanori Kondoh

Koji Bato

Tomoyuki Sakata

Haruki Tanaka

Yoshinori Tochiki

Katsumi Sugawa

Eiji Iida

Tsutomu Tsurumi

Hiroyuki Matsumoto

Gaku Kimura

Kouji Nekoda

Haruka Miyazaki

Kousuke Nakamura

An optical hub node apparatus can be configured to include N+1 or more route units () by connecting N or less route units () selected from among the N+1 or more route units () to a route unit () including N (N:integer of 2 or more) ports to which other route units () are detachably connected. As a result, as compared with a case where N+1 route units () are completely interconnected in a meshed manner, the number of the route units () can be increased. Thus, the number (degree) of optical transmission apparatuses connectable to the optical hub node apparatus can be increased.

Degree extending method and optical hub node apparatus

A measurement apparatus for measuring an optical fiber transmission line used to connect to an opposite apparatus, the measurement apparatus includes a transmission part for generating a measurement packet used for measuring a length of a first and second optical fiber transmission line, and transmitting the measurement packet to the opposite apparatus through the first optical fiber transmission line, a reception part for detecting the measurement packet returned from the opposite apparatus that perform a loopback processing of the measurement packet through the second optical fiber transmission line, a calculation part for calculating a packet transmission time which is a processing time required from the generation of the measurement packet to the detection of the measurement packet, and a measurement part for performing a measurement control of the length of the first and second optical fiber transmission line based on the packet transmission time calculated by the calculation part.

Optical fiber transmission line measurement apparatus and system

The present invention relates to a signal processing device and a signal processing method that are capable of processing various types of signals. The signal processing device comprises a frequency detecting unit detecting a frequency of a data signal by checking synchronization between the data signal and a reference signal, an oscillation unit supplying the reference signal to the frequency detecting unit, a frame detecting unit detecting a frame organizing the data signal, and a control unit changing a frequency of the reference signal supplied by the oscillation unit to take frequency synchronization between the data signal and the reference signal in checking the synchronization by the frequency detecting unit, and setting information of the frequency, of which the frequency synchronization has been taken, in the frame detecting unit.

Signal processing device and signal processing method

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 transmission device includes: an attenuator that attenuates an optical signal before being input into an optical element by a predetermined attenuation amount determined so that a level of an adjustment optical signal input into the optical element falls within a predetermined dynamic range of the optical element; and a controller that adjusts the predetermined attenuation amount so that a level of the optical signal input into the optical element falls within the predetermined dynamic range.

Optical transmission device for controlling optical level of transmission signal in optical transmission system

In each node of an optical transmission system: an optical preamplifier has an ALC function for maintaining an optical output level constant and an AGC function for maintaining the gain constant; the operational mode of the optical preamplifier is changed from an ALC mode to an AGC mode after the gain is set in the ALC mode; an optical postamplifier has an AGC function; an optical switch unit performs an optical crossconnect operation; and a thru-light-shutoff control unit makes a switch setting so as to shut off pass-through light in the optical switch unit and stop transmission of an optical signal having an unstable level to a next stage when the optical preamplifier operates in the ALC mode, and clears the switch setting when the operational mode of the optical preamplifier is changed to the AGC mode.

Optical transmission system

A WDM optical transmission apparatus is disclosed utilizing ASE light. The WDM optical transmission apparatus includes a pre-amplifier having two control modes consisting of ALC mode in which the gain of an optical amplifier is controlled such that the total output of the optical amplifier is constant for a multiplexed wavelength number n, and of AGC mode which is a control mode maintaining constant the ratio of an optical input level to an optical output level for the multiplexed wavelength number n; and a post-amplifier having two control modes consisting of ASE mode in which the gain of the post-amplifier is set higher than that in the AGC mode and is set such that the output level of ASE light corresponds to the multiplexed wavelength number n, and of the AGC mode; wherein in the ASE mode, the gain of the pre-amplifier in the WDM optical transmission apparatus at the next node is set under an ALC control utilizing ASE light output from the post-amplifier.

Pre-amplifier gain setting method utilizing ASE light and WDM optical transmission apparatus employing the method

The gain control circuit controls the amplification ratio of EDFA based on the results of having measured the input power monitor which monitors the EDFA input optical level which amplifies light and of having measured the output power monitor which monitors the output optical level. The optical pre-amplifier receives a notice of the number of wavelengths from a fore node and a notice of whether the optical post-amplifier of a fore node is in normal operation by a supervisory control signal, and changes over the gain control circuit to either the ALC or AGC mode. When the number of wavelengths changes while the optical pre-amplifier is operating in the ALC mode, the optical pre-amplifier is controlled in the AGC mode using the backed-up amplifier gain. Also, the gain value when the optical pre-amplifier is in routine operation is backed up in an amplifier gain back-up unit and an back-up unit.

Optical amplifier supervisory control method in WDM communication system

A link configurator capable of freely forming a physical link configuration per node. This link configurator has a first selective switch logic group for selecting the termination or the relay of a first data stream on a near-end aggregate or tributary side, a second selective switch logic group for selecting the termination or the relay of a second data stream on a far-end connecting side to an adjacent node group, and a connecting group for connecting the first and the second selective switch logic groups. The first and second selective switch logic groups are set to have a terminating or relaying function by a selective control signal.

Universal link configurator for physical link configurations in a data

Growing community of inventors

Kawasaki, Japan

Taro Asao