Kokusai Denshin Denwa Kabushiki Kaisha

Kddi Corporation

Other

Mitsubishi Denki Kabushiki Kaisha

Kddi Submarine Cable Systems Inc.

Kokusai Denshin Denwa Co., Ltd.

Kdd Submarine Cable Systems, Inc.

Kdd Corporation

Yukio Horiuchi

Shu Yamamoto

Masatoshi Suzuki

Shigeyuki Akiba

Toshio Kawazawa

Takashi Mizuochi

Hideki Goto

Shiro Ryu

Yasunori Kasahara

Kenkichi Shimomura

Daishi Ishii

Noboru Edagawa

Hiroharu Wakabayashi

Kiwami Matsushita

Aritomo Uemura

Koji Goto

Yoshinori Namihira

Kiyohumi Mochizuki

An OLT includes a first transmitter and receiver unit for transmitting and receiving signals with ONUs, a first communication control timer, a measurement unit for measuring a round trip time (RTT) between the OLT and each of ONUs, an advance notice time generation unit for generating an advance notice time signal by adding a predetermined time to a time information that indicates a time in the first communication control timer in response to a first time reference pulse, and a unit for controlling the first transmitter and receiver unit to transmit the generated advance notice time signal to each of the ONUs, and to transmit signals indicating measured RTT/2 to the respective ones of the ONUs.

Optical transmission system and synchronization method using time reference pulse

To inform a location of a caller to the other party in an IP phone system, a wireless IC tag preserving unique ID information is attached to an optical connector of a user connection port. The relations between locations of the optical connectors and ID information of corresponding wireless IC tags are stored in a port control database. An IC tag reader in an optical network unit (ONU) reads the ID information in the wireless IC tag attached to the optical connector to which the ONU is connected. When an emergency call is initialed, the ONU transmits destination information of the emergency call and the ID information of the wireless IC tag to a central station. A control terminal in the central station compares the ID information of the wireless IC tag against the port control database to determine a location of the optical connector. The central station adds the determined location information to the destination information of the emergency call and transmits the information to an IP network.

Method to provide caller's location in IP phone system, optical transmission system, optical connector, and optical network unit

In a communication system wherein a station transceiver and a plurality of nodes communicate in a TDM system through a signal transmission line, at least a part of the line is shared, a method to judge nodes performing normal operation from the station transceiver comprises a request step to request a return of a test pattern by transmitting a trigger signal for a designated node in the plurality of nodes, a correlation process step to process correlation between a received signal in a timeslot assigned to the designated node and a reference pattern corresponding to the designated node, and a judging step to judge whether the designated node is a normal node according to the correlation process result.

Node judging method, communication system, and node measuring apparatus

An optical repeating system includes an optical transmitter and a plurality of optical amplifying repeaters. The optical transmitter specifies a part or all of the optical amplifying repeaters, and transmits a supervisory command to the specified optical amplifying repeaters as a first sub-signal via an uplink or downlink optical transmission line. The supervisory command is a command to supervise internal circuits of the optical amplifying repeaters. Receiving the supervisory command addressed thereto via the uplink or downlink optical transmission line, the optical amplifying repeaters each transmit a supervisory signal indicating a supervisory result corresponding to the supervisory command to optical receivers via the uplink and downlink optical transmission lines as a second sub-signal. The optical system can reduce the time take to acquire the supervisory information about the plurality of the optical amplifying repeaters.

Optical repeating system and optical amplifying repeater control method

This invention discloses a method to easily extract a header from an optical packet. An optical data transmission method to transmit an optical packet composed of a header and data containing steps of generating a second clock which has a frequency equal to one integer of that of a first clock carrying the data and synchronizes with the first clock, and carrying the header information on the second clock.

Optical data transmission method and its system, optical transmitter and its method, and optical switcher

An optical repeating system includes an optical transmitter and an optical amplifying repeater. The optical transmitter transmits a supervisory command and a control command to the optical amplifying repeater as a first sub-signal. The supervisory command is a command to supervise internal circuits of the optical amplifying repeater, and the control command is a command to control the optical amplifying repeater. The optical amplifying repeater includes multiple sub-modules each for amplifying and repeating main signals on multiple sets of optical transmission lines. When receiving the supervisory command via the optical transmission line, each sub-module transmits a supervisory signal indicating the supervisory result associated with the supervisory command to an optical receiver as a second sub-signal. In addition, when receiving a predetermined control command via the optical transmission line, each sub-module initializes another sub-module of the multiple sub-modules in response to the predetermined control command. The optical amplifying repeater can restart its control program even when it has fallen into a state where it is difficult to continue to execute the normal operation in accordance with the control program because of some exception or the like.

In an optical repeating system including an optical transmitter and optical amplifying repeaters, the optical transmitter specifies one optical amplifying repeater, and transmits to the optical amplifying repeater a supervisory command to supervise internal circuits of the optical amplifying repeater and a control command to control amplification factors of optical amplifiers of the optical amplifying repeater as a first sub-signal. Receiving the supervisory command via an optical transmission line, the optical amplifying repeater transmits a supervisory signal indicating a supervisory result corresponding to the supervisory command to optical receivers via optical transmission lines as a second sub-signal. Receiving the control command via the optical transmission line, the optical amplifying repeater is controlled to change amplification factors of the optical amplifiers in response to the control command.

The optical amplifier according to the present invention is constructed such that the amount of the electric current fed to the power feeding lineis first detected by the current detection means, and then a setting signal is generated to each of the bypass circuitsandin accordance with the thus detected amount of the fed current, and thereafter the output level of each of the optical repeater circuitsandis controlled respectively by the bypass circuitsand, so that the output level of these repeater circuitsandcan be controlled in accordance with the amount of the current fed to the power feeding line

Optical amplifier having various control circuitry

A supervisory system and supervisory method of an optical amplifier repeater are proposed that can implement operation supervision taking account of the characteristics of individual supervisory targets of the optical amplifier repeater, thereby achieving higher reliability. The supervisory system includes an optical transmitter for transmitting an optical signal including an operation command to notify of a state of a supervisory target; an optical amplifier repeater that transmits a response optical signal including a response code obtained by measuring the supervisory target in response to the operation command; an optical receiver for receiving the response optical signal via an optical fiber and an information processing unit for converting the response code into a numerical form by using a predetermined expression that links the response code with measured information obtained by measuring in advance the supervisory target with an external measuring device during operation of the optical amplifier repeater in response to the operation command.

Supervisory system of optical amplifier repeater system and supervisory method of optical amplifier repeater system

The optical amplifier according to the present invention is constructed such that the amount of the electric current fed to the power feeding line is first detected by the current detection means, and then a setting signal is generated to each of the bypass circuits and in accordance with the thus detected amount of the fed current, and thereafter the output level of each of the optical repeater circuits and is controlled respectively by the bypass circuits and , so that the output level of these repeater circuits and can be controlled in accordance with the amount of the current fed to the power feeding line

A measuring system of transmission characteristics comprises a reference signal light generator for generating reference signal light of a reference wavelength optically intensity-modulated at a reference frequency, a measuring signal light generator for generating measuring signal light of a measuring wavelength optically intensity-modulated at a measuring frequency synchronizing with the reference frequency, a multiplexer for multiplexing the reference signal light and measuring signal light respectively generated by the reference signal light generator and measuring signal light generator and outputting them onto a to-be-measured optical line, a photodetector for converting the lights propagated on the to-be-measured line into electric signals, a reference frequency extractor for extracting the component of the reference frequency from the output of the photodetector, and a phase detector for detecting a phase of a frequency component corresponding to the measuring frequency contained in the output of the photodetector according to the output of the reference frequency extractor.

Measuring system of transmission characteristics

An optical repeater monitoring system, according to the invention, comprises an oscillating source, a reference signal transmitter for transmitting a reference signal of a predetermined frequency generated from an output of the oscillating source to a first optical fiber, and an optical repeater. The optical repeater has a first photodetector for converting light from the first optical fiber into an electrical signal, a reference signal extractor for extracting a component of the reference signal from an output of the first photodetector, a carrier generator for generating a carrier from an output of the reference signal extractor, a monitor signal modulator for modulating the carrier generated by the carrier generator with a monitor signal showing a operating state of the optical repeater, a transmitter for transmitting an output of the monitor signal modulator to a second optical fiber. The system further comprises a demodulating signal generator for generating a demodulating signal from either of the output from the oscillating source and the reference signal, the demodulating signal having a frequency equal to that of the monitor signal carrier, a second photodetector for photodetecting the light propagated on the second fiber, and a monitor signal demodulator for demodulating the monitor signal from outputs of the second photodetector and demodulating signal generator.

Optical repeater monitoring system and a method thereof

An apparatus for monitoring and measuring condition of a plurality of optical transmission lines individually according to this invention comprises at least one reflecting means having a predetermined reflection bandwidth arranged on each of said optical transmission lines; an optical pulse tester for outputting probe pulse light having predetermined wavelength in the reflection bandwidth of said reflecting means, and analyzing the reflected light of said probe pulse light in a time domain; optical coupling means for adding said probe pulse light from said optical pulse tester and a signal light, and coupling it to each of optical transmission lines through optical dividing means, along with coupling the reflected light of said probe pulse light to said optical pulse tester; and a plurality of optical filters arranged on the input end of each of said optical transmission lines for transmitting wavelength of signal light to be transmitted on their respective optical transmission lines and the predetermined wavelengths to be reflected on the reflection means on corresponding optical transmission lines. The predetermined wavelengths of a plurality of optical filters are different from each other.

Optical transmission line monitoring apparatus

A control signal superimposer for superimposing a control signal on a signal light, comprising a pumping light source for generating a pumping light with intensity fluctuation in accordance with the control signal; a Raman amplification medium pumped by the pumping light from the pumping light source for Raman-amplifying the signal light; a combiner for combining the pumping light output from the pumping light source and the signal light to be Raman-amplified and then supplying them to the Raman amplification medium; and an optical filter for extracting the signal light component from the output light of the Raman amplification medium and terminating the pumping light component.

Control signal superimposer

Disposing optical fiber gratings,each reflecting a wavelength &lgr;1 which is different from a signal wavelength &lgr;s along an optical fiber line,at suitable intervals and positions. The wavelength &lgr;s of signal light is not reflected by the grating,, but transmitted through the optical fiber line,. An optical pulse tester,outputs probe pulse lights of wavelengths &lgr;0, &lgr;1, which are different from the signal wavelength &lgr;s, at slightly different times. The probe lights of the wavelengths &lgr;0, &lgr;1 are input into the optical fiber line,through an optical adding and dividing device,and transmitted through the optical fiber line,. Reflected light of the wavelength &lgr;1 of probe light contains therein reflection pulses of the grating,, and each reflection pulse serves as a position reference. The probe light of the wavelength &lgr;0 does not contain reflection light of the grating,. Comparison of the reflected lights of the wavelengths &lgr;0, &lgr;1 to each other by the optical pulse tester,, provides determination of whether there is a fault location, and, if so, detection of fault location with high precision can be made.

Growing community of inventors

Saitama, Japan

Yukio Horiuchi