Fujitsu Corporation

Kazuo Takatsu

Atsuki Taniguchi

Yoshinori Nakamura

Takeshi Sakamoto

Koji Takeguchi

Kenji Fukunaga

Akihiko Oka

Kimio Uekama

Yoshinori Tochiki

Takumi Iwai

Tomoaki Takeyama

Masahiro Yuki

Kanta Yamamoto

Masanori Arai

Hideaki Mochizuki

Masahiro Shinbashi

Katsuichi Ohara

Junichi Ishiwatari

Nobuyuki Nemoto

Naonobu Fujimoto

Shosaku Yamasaki

Masakazu Mori

Takashi Umegaki

Nobuo Iguchi

Hiroaki Mori

Toshiharu Sakai

Toshihito Echizenya

Nobuhide Yamaguchi

Toshikazu Ota

Miki Hagino

Koji Iwamoto

An optical transfer method of an optical transfer system including a transmitter, a first wavelength converter configured to use first excitation light to perform wavelength-conversion of first signal light which is the transmission light into second signal light in a different wavelength band, a second wavelength converter configured to use second excitation light to perform wavelength-conversion of the second signal light into third signal light in a different wavelength band, and a receiver configured to receive the third signal light, the method includes acquiring a wavelength of the transmission light, a wavelength of the first excitation light, and a wavelength of the second excitation light; and deciding local emission light of the receiver based on a wavelength of reception light of the receiver obtained from the wavelength of the transmission light, the wavelength of the first excitation light, and the wavelength of the second excitation light.

Optical transfer system, control device, optical transfer method, and transfer device

An optical add-drop multiplexer having first and second routes includes: an optical cross connect; a first multiplexer optically coupled to a plurality of output ports of the optical cross connect; a second multiplexer optically coupled to a plurality of other output ports of the optical cross connect; a first wavelength selective switch to generate a first WDM optical signal including an optical signal output from the first multiplexer and to guide the first WDM optical signal to the first route; and a second wavelength selective switch to generate a second WDM optical signal including optical signal output from the second multiplexer and to guide the second WDM optical signal to the second route.

Optical add drop multiplexer

There is provided an optical transmission device, the optical transmission device including a wavelength selective switch configured to select a first optical signal having a first wavelength from an input signal of wavelength division multiplexing, an optical filter circuit configured to include an optical tunable filter having a pass wavelength that is tunable to a second wavelength of a second optical signal for passing therethrough, a splitter configured to split the input signal, a split signal split by the splitter being transferred to the optical filter circuit, and a coupler configured to couple the first optical signal selected by the wavelength selective switch and the second optical signal passed through the optical filter circuit.

Optical transmission device and optical filter circuit

An optical switching device includes plural wavelength selective switches that respectively have a first port and a plurality of second ports; and an optical coupler that has a plurality of third ports on an input-side or an output-side, respectively optically coupled to the first ports of the wavelength selective switches.

Optical switching device, optical add device, and optical drop device

The present invention is a technology concerning a reception pointer processing in an SDH transmission system. The objects of the invention are to identify automatically a frame size (frame composition) of the received transmission frame in the SDH (SONET) transmission system and to perform flexibly and rapidly a reception pointer processing corresponding to the frame size. These objects are realized by providing a reception pointer processing apparatus for performing the pointer processing of the transmission frame transmitted by the SDH transmission system, wherein the reception pointer processing apparatus comprises a pointer processing section for executing the required pointer processing of each unit frame contained in the transmission frame, and a frame composition identification section for identifying automatically the frame composition of the transmission frame based on the pointer processing result of the pointer processing section and for providing the identification result to the pointer processing section.

Reception pointer processing apparatus in SDH transmission system

Technology for detecting a frame synchronous pattern that includes a data switch section for performing data rearrangement processing of parallel data having a given frame synchronous pattern; a temporary region detection section for temporarily detecting a candidate of region data containing the frame synchronous pattern from the parallel data; a frame synchronous pattern detection section for detecting the frame synchronous pattern from the temporary region data of the temporary region detection section; and a data switch control section for controlling data rearrangement processing by the data switch section according to the detection state of the temporary region data by the temporary region detection section and to the detection state of the frame synchronous pattern by the frame synchronous pattern detection section, in order to detect precisely the frame synchronous pattern in m parallel data without enabling the detection of m ways of frame synchronous patterns in in parallel data.

Frame synchronous pattern processing apparatus and frame synchronous pattern detection apparatus and method for detecting frame synchronous pattern

An optical transmission device has an optical amplifier, first and second control signal reception units and a transmission unit. The first control signal reception unit receives control signals from a receiving end optical service channel. The second control signal reception unit receives control signals from an operator. The transmission unit transmits to the optical amplifier, either the control signals from the receiving end optical service channel or the control signals from the operator so that the optical amplifier operates in either an automatic level control mode or an automatic gain control mode.

Light wavelength-multiplexing systems

A wavelength-division multiplexing optical communication system for wavelength-division multiplexing a plurality of optical signals having different wavelengths and transmitting a wavelength-division multiplexed signal via an optical fiber transmission line. The wavelength-division multiplexing system includes a multiplexing unit that wavelength-multiplexes a plurality of optical signals having different wavelengths. A storing unit stores information regarding an addition or subtraction of an optical signal to be wavelength-multiplexed, into a predetermined time slot of a frame signal that is composed of a plurality of time slots. The wavelength-division multiplexing system outputs a monitor/control frame signal, based upon the stored information. A transmitting device transmits the monitor/control signal as an optical signal having a wavelength different from the wavelengths of the multiplexed optical signals.

In processing a frame synchronous pattern, a data switch section arranges in such a manner that an object frame synchronous pattern comes as a start of the parallel data, and a provisional-region detection section for samples, among the parallel data, a part in which the object frame synchronous pattern is presumably located, as a provisional region, and converts the parallel data of the provisional region in serial. And a frame synchronous pattern detecting section detects the object frame synchronous pattern from the partial serial data of the sampling and converted and responsive to the frame synchronous pattern detection section and the provisional-region detection section. A data switch control section, controls the data switch section based on the output of the provisional-region detection section and the output of the frame synchronous pattern detection section.

Two alarm detecting units required as alarm detecting units for controlling a PSW in order to implement a PSR function, are deleted, and instead the result of an alarm detection output by a conventional alarm detecting unit (E-THRU) for a BLSR function is cross-connected in units of STS-1 frames by an alarm TSA apparatus (E-DROP). In the same way, the result of an alarm detection output by an alarm detecting unit (W-THRU) is cross-connected in units of STS-1 frames by an alarm TSA apparatus(W-DROP). These two cross-connected alarms are compared by a comparing unit (DROP). Based on the result of the comparison the PSW is controlled.

Path switching device for transmission apparatus

A communications system has two transmission circuits, each transmitting a multiplexed signal in both ways. A repeating installation used therein selects either one of the two transmission circuits and terminates management information contained in a signal which flows through a transmission circuit selected by the selecting unit. The repeating installation sets the other non-selected transmission circuit to be in a high impedance state. The selection and termination are commonly performed for the two transmission circuits, and the repeating installation further extracts the management information transmitted and outputs the management information to be outputted. The management information includes a section overhead having management information concerning a repeating section of the communications system, and the repeating installation does not terminate management information concerning a multiplex section. One of the two transmission circuits includes a spare transmission circuit.

Repeating installation

A connection switching circuit is disposed in each node of a ring system in which a first ring and a second ring are provided with two communication lines which allow data to flow in a different direction respectively and is connected with a currently used passage and preliminary passage. The connection switching circuit comprises an alarm correction reading part for generating a control signal, an alarm monitor part for outputting respective alarm detection signals, a currently used/and preliminary alarm recognition part, and a switching control signal generation part for generating a control signal for selecting a passage, wherein either the currently used passage or the preliminary passage is selected by monitoring the alarm of the data which flows on the currently used passage or the preliminary passage to connect the first ring and the second ring with each other.

Connection switching circuit for ring system

There is provided a different system transfer method for a ring transmission system and a transmission apparatus for transferring the ring transmission system constructed in the UPSR system to the BLSR system while a line is in service. A control board of the UPSR system is replaced by a control board of the BLSR system. By changing over a path switch, a multiplexing/demultiplexing conversion board of the UPSR system on the non-operating side is replaced by a first multiplexing/demultiplexing conversion board of the BLSR system which is set so as to operate in the UPSR system. Also, by changing over the path switch again, a multiplexing/demultiplexing conversion board of the UPSR system on the non-operating side is replaced by a second multiplexing/demultiplexing conversion board of the BLSR system which is set so as to operate in the UPSR system. Next, the first and second multiplexing/demultiplexing conversion boards are made to operate in the BLSR system, and a line arrangement is changed from the UPSR system to the BLSR system.

Different system transfer method for a ring transmission system and

An add-drop multiplexer contains a partial drop unit and a partial add unit. The partial drop unit selects a number n of first signal(s) of n channel(s) among a number N of first signals of N channels, which are received from a first transmission line, and transmits the n first signal(s) of n channel(s) on at least one second transmission line, where N and n are integers satisfying N&gt;n&gt;0. The partial add unit receives n second signal(s) of n channel(s) from at least one third transmission line, and a number (N-n) of first signal(s) of (N-n) channel(s) among the N first signals of the N channels, which are not selected by the partial drop unit, and transmits on the first transmission line the n second signal(s) of n channel(s) and the (N-n) first signal(s) of (N-n) channel(s) as N third signals of N channels.

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Kawasaki, Japan

Kazuo Takatsu