Fujitsu Corporation

Makoto Shimizu

Kosuke Komaki

Junichi Sugiyama

Taku Saito

Hiroshi Nishida

Hirofumi Araki

Shota Shinohara

Taketo Endo

Toshihiro Suzuki

Hisao Nakashima

Yuji Ikegami

Masato Hori

Hiroyuki Homma

Wataru Odashima

Ichiro Yokokura

Takeshi Noma

Hidenori Sugai

Shuzo Matsushita

First transmission device includes a first counter that generates counter value incremented in a specified cycle. Second transmission device includes a second counter that generates counter value incremented in the specified cycle. Polarization variation monitoring device acquires a first counter value generated by the first counter and a second counter value extracted by the first transmission device from a received frame transmitted from the second transmission device when the first transmission device detects polarization variation, and a third counter value generated by the second counter and a fourth counter value extracted by the second transmission device from a frame transmitted from the first transmission device when the second detector detects the polarization variation. The polarization variation monitoring device determines an occurrence position of the polarization variation based on the first counter value, the second counter value, the third counter value and the fourth counter value.

Polarization variation monitoring system and polarization variation monitoring method

An optical transmission apparatus includes: a coherent detector configured to receive light including different polarization components from an optical transmission path, and perform coherent detection of received light including the different polarization components; an adaptive equalizer configured to adaptively equalize, by a digital filter, a complex electric signal for each of the polarization components obtained by the coherent detection, a gain value for controlling an amplitude of the complex electric signal being applied to the complex electric signal; and a polarization dependent loss monitor configured to determine a polarization dependent loss of the optical transmission path, based on a correction filter parameter obtained by correcting a filter parameter of the digital filter according to the gain value, the filter parameter being adaptively updated by an adaptive equalization of the adaptive equalizer.

Optical transmission apparatus, optical transmission system, and polarization dependent loss monitor

There is provided a frame converter that writes input data included in an input frame to a buffer to accumulate the input data and outputs data read from the buffer as output data included in an output frame, the frame converter includes a setting unit configured to set a time interval from start of resizing of data rate of the input data to start of resizing of data rate of the output data when resizing of an accumulation amount in the buffer is performed in which data rates of the input data and the output data vary, and an adjustment unit configured to adjust to approximate the data rate of the output data to the data rate of the input data after the time interval has elapsed since the start of resizing of data rate of the input data.

Frame converter and frame conversion method

An optical transmission apparatus includes: an optical receiver configured to receive an optical signal; a variable optical attenuator configured to adjust a power of the optical signal to be input to the optical receiver according to a variable attenuation amount; and a controller configured to control the attenuation amount of the variable optical attenuator based on an electrical signal obtained by performing a coherent detection and a photoelectric conversion on the optical signal received by the optical receiver.

Optical transmission apparatus and method for controlling optical power

A relay device for dividing a storage device into a plurality of unit areas, assigning an unused unit area from among the plurality of unit areas to received channel-specified data, and performing at least one of adjustment of a transmission timing of the data and conversion of the data by using the assigned unit area, is disclosed. The relay device includes an error detector configured to detect an error where the unit area from which the data is to be read is not specified; and an error control configured to recognize a channel of data stored in the unit area that is not specified due to the error detected by the error detector as a target channel, and to invalidate an assignment of the unit area to the recognized target channel.

Relay device and recovery method

A clock conversion apparatus comprising, an elastic store memory in which data are written in synchronization with a first clock and from which data are read out in synchronization with a second clock, a phase comparator for detecting phase difference between a third clock obtained by imparting a first variable phase shift to a divided clock of the first clock and a fourth clock obtained by imparting a second variable phase shift to a divided clock of the second clock, and an oscillator for generating a clock having frequency in accordance with the phase difference as the second clock.

Clock conversion apparatus with an elastic store memory from which data is written in synchronization with a first clock and read out in synchronization with a second clock

A transmission apparatus for transmitting frames accommodating client data over a transmission network, comprising a clock generation unit that generates a clock for timing processing period of signal processing, a deviation detection unit that detects clock deviation between the clock generated by the clock generation unit and the clock used for timing processing period of signal processing by other transmission apparatus that receives the client data from outside the transmission network and adds them to frames, and a timing generation unit that generates timing signal of processing period of signal processing corrected with the clock deviation.

Transmission apparatus, transmission method and method of altering transmission band

A rate monitoring apparatus using a token bucket algorithm for controlling a packet flow, the apparatus includes a packet information storage unit having two storage media for storing packet information extracted from a packet data, a token identifying information storage unit having two storage media for storing identification information used for supplying a created token, and an operation unit for performing a policing operation by using a packet length, an allowable burst size, a token supply capacity and a currently transmittable data capacity, based on an identifying information included in the packet information and a comparison result between identification information included in the packet information and the identification information used for supplying the created token, these compared identification information being read out from the other storage medium different from the storage medium under writing in the packet information storage unit and the token identifying information storage unit.

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Oyama, Japan

Makoto Shimizu