Kokusai Denshin Denwa Kabushiki Kaisha

Other

Kokusai Denshin Denwa Co., Ltd.

Kdd Corporation

Mitsubishi Denki Kabushiki Kaisha

Kdd Submarine Cable Systems, Inc.

Kddi Corporation

Kabushiki Kaisha Toshiba

Shu Yamamoto

Noboru Edagawa

Shigeyuki Akiba

Hidenori Taga

Masatoshi Suzuki

Yukio Horiuchi

Tetsuya Miyazaki

Itsuro Morita

Hiroharu Wakabayashi

Tadayoshi Kitayama

Kiwami Matsushita

Takashi Mizuochi

Norio Seki

Aritomo Uemura

Haruo Sakaguchi

Noriyuki Takeda

Katsuhiro Shimizu

Tomohiro Otani

Takayuki Miyakawa

Naoki Kobayashi

Keiji Tanaka

Takaya Yamamoto

Hideaki Tanaka

Yoshinao Iwamoto

Hiroshi Ichibangase

Yotaro Yatsuzuka

Takatomi Kabashima

Takeshi Komiya

Kazuo Hashimoto

Akira Okada

Yoshihiro Yoshida

Katsuyuki Yamazaki

Yuichi Matsushima

Hisato Uetsuka

Koji Goto

Tazuko Tomioka

Katsuyuki Yamamoto

Kuniaki Motoshima

Hiroyuki Ibe

Shiro Ryu

Kiyofumi Mochizuki

Hidetoshi Yokota

Shigeru Ohshima

Yasuyuki Nagao

Senji Shimanuki

Carl Edward Williams

Manish Sharma

Koichi Maru

Mitsuko Nakamura

Katsumi Takano

Hitoshi Takahira

Kaoru Imai

Tetsuyuki Miyakawa

Yojiro Osaki

Tadayoshi Mitsubishi Denki Kitayama

Aritomo Mitsubishi Denki Uemura

Takashi Mitsubishi Denki Mizuochi

Hiroshi Mitsubishi Denki Ichibangase

A mobile IPv6 dual-stack node engages in IPv6 communication while roaming within an IPv4-only network, for example using ISATAP. First, the node determines that it has moved Bnd obtains a new IPv4 address. After determining that the visited network contains no IPv6-enabled components, the node uses an IPv6 connect agent to engage in IPv6 communication. The node configures its care-of address using the IPv6 connect agent's routing information and the node's newly-obtained IPv4 address. In one embodiment, the node and the connect agent optimize the handoff when the nodes has moved but still uses the same connect agent. The node sends a binding updates to the connect agents comprising the node's old care-of address and the node's new care-of address. When the connect agent receives a packet destined for the node's previous care-of address, it forwards the packet to the node's currents care-of address, thereby reducing packet loss.

Enabling mobile IPv6 communication over a network containing IPv4 components using ISATAP

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

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

The present invention has an object to obtain an optical signal quality supervisory device that supervises the quality of an optical signal simply, efficiently and with high accuracy without inviting an increase in cost, an increase in circuit scale and increase in power consumption. The bit rate of the optical supervisory channel is made lower than the bit rate of the optical main channel that is transmitted over an optical communication system, but the reception electric band width of a receiver that receives the optical supervisory channel is made equal to or wider than the reception electric band width of a receiver that receives the optical main channel. Also, the optical supervisory channel is made up of an SOH (section over head) frame to detect an error of the BIP (bit interleaved parity) byte of SOH, thereby supervising the quality of the optical communication system, in particular, the light wave network.

Optical signal quality supervisory device

A four fiber ring network optical switching circuit capable of realizing the bridge function at times of the span switching and the ring switching economically by a very compact structure is disclosed. A four fiber ring network optical switching circuit is formed by a 10&times;8 optical matrix switch having ten input ports and eight output ports, and two branching elements adapted to branch each one of two optical signals among eight optical signals that are inputs of the four fiber ring network optical switching circuit, into two identical optical signals, and to enter the two identical optical signals into two input ports of the 10&times;8 optical matrix switch such that the eight optical signals are entered into the ten input ports of the 10&times;8 optical matrix switch as ten optical signals.

Four fiber ring network optical switching circuit using branched inputs

In a signal demultiplexing device formed by a probe light source, a wavelength converter, and a wavelength demultiplexer, the probe light source is formed by a plurality of sub-probe light sources configured to respectively generate the sub-probe lights with the prescribed different wavelengths for respective time-slots, a multiplexer configured to multiplex the sub-probe lights generated by the plurality of sub-probe light sources, and a phase different giving unit configured to give phase differences corresponding to time-slot positions to the sub-probe lights multiplexed by the multiplexer, and to sequentially output the sub-probe lights with the phase differences in correspondence to respective time-slots.

Signal demultiplexing device and signal routing device in high speed transmission 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

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 optical digital regenerator for digitally regenerating an input signal in an intact optical state. A first operating unit has a first probe light generator for generating a first probe light and a first optical operator for converting a waveform of the first probe light output from a first probe light generator according to an optical intensity waveform of the input signal light. A clock extractor extracts a clock component of the input signal light from a photocurrent generated by the first optical operator. A second optical operating unit has a second probe light generator for generating a second probe light pulsed in accordance with the clock output from the clock extractor and a second optical operator for sampling the second probe pulse light output from the second probe light generator.

Optical digital regenerator

To increase the number of multiplexed wavelengths and to improve transmission characteristics in a wavelength-division-multiplexed transmission, a bandwidth compressor for bandwidth-compressing the wavelength-division-multiplexed signal light is disposed at a front part of respective optical amplifiers and a bandwidth expander for bandwidth-expanding the wavelength-division-multiplexed signal light output from said optical amplifiers is disposed at a rear part of said optical amplifiers.

Optical amplifying transmission system and optical amplifier

A laser diode continuously laser-oscillates and its output light is applied to an optical modulator. A pulse driver drives the optical modulator according to a data to be transmitted. A phase modulator is driven by a phase modulator driver and phase-modulates the output from the optical modulator. The polarization direction of the incident light of the phase modulator is set so that the modulation efficiency of the phase modulator becomes the maximum. The output light of the phase modulator inputs a birefringent medium and applies to an optical transmission line after transmitting the birefringent medium. The principal axis of the birefringent medium is disposed so as to be at an angle of 45&deg; to the polarization direction of the output light from the phase modulator.

Optical transmitting apparatus

Detection of an optical pulse position uses an optical pulse string with a determined repetitive ratio and an electric clock signal with a same frequency as the repetitive ratio of the optical pulse string. A phase of the electric clock signal oscillator is shifted and supplied to an optical modulator. The optical modulator modulates the optical pulse string based on the electric clock signal and outputs a modulated optical signal. A photo detector converts the modulated optical signal output from the optical modulator to an electric signal. The phase shift amount of the electric clock signal is controlled to maximize an output from the photo detector. Additionally, a dither signal may be used in the control of the phase shift, more than the optical modulator may be employed, and/or more than color light source may be employed. The use of at least one of feed forward and feedback control provided by maximizing an output of the photo detector allows an optical pulse having a short width to be realized.

Optical pulse position detecting circuit and an optical pulse generating apparatus and their methods

An optical switching system is implemented by providing a transmitting section with a preparatory transmitted optical signal selector and a working transmitted optical signal splitter, which are each implemented by a 1&times;2 optical space switch, and by providing a receiving section with a receiving optical switch which is implemented by a 2&times;2 optical space switch, and with a preparatory receiving optical gate which is implemented by a 1&times;2 optical space switch. This makes it possible to switch between the working system and preparatory system without employing any 4&times;4 optical space switch, thereby implementing a practical optical switching system without causing such problems as communication interruption during maintenance or impairment of transmission path working efficiency.

Optical switching system

An optical wavelength division multiplexed signal amplifying repeater capable of doubling the number of wavelength division multiplexed signals that can be transmitted is disclosed. Optical signals of both 1.3 &mgr;m band and 1.55 &mgr;m band in the entered optical wavelength division multiplexed signals are amplified, while pumping lights capable of causing Raman amplification in the 1.3 &mgr;m band are coupled with the optical wavelength division multiplexed signals so as to cause the Raman amplification for the optical signals of the 1.3 &mgr;m band, such that a difference between the loss in the 1.3 &mgr;m band and the loss in the 1.55 &mgr;m band due to the optical fibers are compensated. An optical communication transmission line using such repeaters is also disclosed.

Optical wavelength division multiplexed signal amplifying repeater and optical communication transmission line with very large capacity

In a light source for generating light containing multiple wavelengths substantially uniform in intensity, a wavelength demultiplexing element,(for example, waveguide-type wavelength selecting filter) demultiplexes input light into a plurality of wavelengths &lgr;,through &lgr;,. Optical amplifiers,-,through,-,amplify outputs of the element,and applies them to input ports of a wavelength multiplexing element,. The wavelength multiplexing element,wavelength-multiplexes their input. Output of the wavelength multiplexing element,is applied to a fiber coupler,which, in turn, applies one of its outputs to the wavelength demultiplexing element,. The optical amplifiers,have a gain larger by approximately 10 dB than the loss in the optical loop made of the element,, optical amplifier,, element,and fiber coupler,. The other output of the fiber coupler,is wavelength-multiplex light containing wavelengths &lgr;,through &lgr;

Multi-wavelength light source and discrete-wavelength-variable light source

Growing community of inventors

Tokyo, Japan

Shu Yamamoto