Fujitsu Corporation

Sumitomo Osaka Cement Co., Ltd.

Trimatiz Limited

Yoichi Oikawa

Satoshi Kuroyanagi

Takeshi Ihara

Kazuaki Akimoto

Hideyuki Miyata

Takuji Yamamoto

Hirofumi Aota

Hiroshi Nagaeda

Hiroshi Hamano

Takashi Toyomaki

Izumi Amemiya

Noriyasu Shiga

Yoshinori Nishizawa

Yumi Nakazawa, Legal Representative

Norikazu Miyazaki

Toshihiro Ohtani

Toshio Kataoka

Tsukasa Takahashi

Noriaki Mizuguchi

Kaoru Higuma

Takehisa Ishikawa

Makoto Murakami

Masahito Mure

Teruhiro Kubo

Tomoyuki Ohtsuka

Masahide Miyachi

Hiroyuki Sato

Yoshiaki Horiuchi

An optical apparatus comprising, converting units converting electrical signals into signal lights with different wavelength, polarization control units controlling polarizing states of the signal lights into polarization controlled lights respectively, an optical multiplexer multiplexing the polarization controlled lights into a multiplexed light, an optical branching unit branching the multiplexed light and outputting a branched light, a polarizing unit extracting only signal lights of the specified polarizing state from the branched light into an extracted light, and a control unit detecting intensity of the extracted light. Pilot signals are applied to modulate the electrical signals or the polarization controls. The polarization control units controls the polarizing states of the signal lights based on the pilot signal frequencies of the detection result by the control unit.

Optical apparatus using polarized orthogonal control

The present invention relates to an optical receiver, and particularly, to an optical receiver by which a DQPSK-modulated optical signal is demodulated to a multilevel phase-modulated signal.

Optical receiver

A high-speed optical amplifier is considered to be an important optical device because of an increasing demand of routing, which is accompanied by an increase in complexity of networks. It is difficult to satisfy a response performance by related-art techniques, and there has been a problem in achieving a high-speed response performance of 10 microseconds or less. An optical amplifier according to the present invention includes: an input monitor means; an optical amplification meansincluding an optical amplification medium, and a control meansfor performing feed-forward control. When the optical amplification means is controlled by the feed-forward control in response to a signal of the input monitor means, an overshoot signal is applied as a control signal so that a slow response performance specific to the optical amplification medium has been improved, and thereby high-speed response performance has been achieved.

Optical amplifier

In a CWDM optical transmission system of the present invention, in place of an optical signal of at least one wave among a plurality of optical signals corresponding to a CWDM system, a DWDM light output from an additional light transmission unit of a DWDM system is given to a multiplexer via a variable optical attenuator, and multiplexed with the optical signals corresponding to CWDM, to be sent out to a transmission path. At this time, the total power of the DWDM light sent out to the transmission path, is attenuated by the variable optical attenuator, so as to be approximately equal to the power per one wavelength of the CWDM light. On an optical reception terminal, the light propagated through the transmission path is demultiplexed by a demultiplexer, and the DWDM light corresponding to the additional wavelengths is amplified by an optical amplifier and thereafter, received by an additional light reception unit. As a result, the addition of optical signals in the CWDM system can be realized at low-cost, while avoiding the reduction in transmission quality.

Coarse wavelength division multiplexing optical transmission system, and coarse wavelength division multiplexing optical transmission method

An optical repeater which includes a wavelength converter and a bit rate converter. The wavelength converter converts a wavelength of an optical signal from a first optical network to a wavelength of a second optical network. The bit rate converter converts a bit rate of the optical signal from the first optical network to a bit rate of the second optical network. The optical repeater transmits the optical signal from the first optical network to the second optical network at the converted bit rate and wavelength.

Optical repeater converting wavelength and bit rate between networks

The distance between an optical diffraction device and a focusing lens, and the coefficient of the focal length change of the focusing lens, are adjusted based on the calculation expression of wavelength identification errors in light of temperature change of a member making up light receiving means (e.g., PD array), thereby performing correction of wavelength identification errors, whereby optical wavelength identification can be performed with high precision even when the temperature changes.

Temperature-independent optical wavelength identification apparatus and optical wavelength identification method

An optical device module includes an optical device, a soaking unit fixed to one surface of the optical device, a heating/cooling unit fixed to one surface of the soaking unit, a heat-insulating unit fixed to one surface of the heating/cooling unit, and a package that houses the optical device, the soaking unit, the heating/cooling unit, and the heat-insulating unit and to which the heat-insulating unit is fixed. The heating/cooling unit heats the optical device using self-generated heat or cools the optical device via the soaking unit.

Optical device module

The invention aims to provide a miniaturized polarization measuring apparatus which can measure the polarization of input signal light with high accuracy, even in an optical system where a plurality of light receiving elements are arranged adjacent to each other. To this end, in the polarization measuring apparatus which branches the input signal light into four signal lights by optical couplers in a three stage configuration, and provides the signal lights with polarizations and the phase shifts, which are different for each signal light, by a plurality of optical elements arranged on branched optical paths, and detects the signal light powers by corresponding light receiving elements, and calculates the Stokes parameters or the like, based on the detection results, to thereby measure the polarization of the input signal light, the elements are arranged to be inclined to each other, so that an interference system is not formed between the adjacent elements on the same branched optical path, and also there is provided a shielding wall so that a stray light generated between these elements does not reach the light receiving element on another branched optical path.

Polarization measuring apparatus

A wavelength selective switch of the invention separates WDM light coming out from an input fiber of a fiber collimator array according to its wavelength, in a diffraction grating, and reflects each wavelength channel proceeding in different directions by MEMS mirrors corresponding to a mirror array. In the MEMS mirrors, the angles of their reflecting surfaces are set corresponding to the location of the output port which is set in the output address of the wavelength channel to be injected. For each of the wavelength channels that reach the target output port, one part of each is reflected by the end face of an output fiber, and the reflected light is returned to the input port, and sent to a channel monitor via an optical circulator, so that the optical power corresponding to each wavelength channel is monitored. As a result it is possible to provide a small size, and low-cost, wavelength selective switch, that can monitor the power of each wavelength channel guided to a plurality of output ports, with good accuracy.

Wavelength selective switch

An optical switch having a plurality of switch cells. The optical switch has n inputs (n is a natural number) and m outputs (m is a natural number). The optical switch has a unit size defined as the distance between any two adjacent ones of the switch cells. The optical switch comprises a substrate having a switch size of K&#xd7;L (K is an integer satisfying n&#x2266;K, and L is an integer satisfying m&#x2266;L), first and second mirrors parallel to each other and perpendicular to a principal surface of the substrate, and an optical unit providing a plurality of input optical paths for the n inputs and a plurality of output optical paths for the m outputs. The plurality of input optical paths are inclined relative to the first and second mirrors, and the plurality of output optical paths are inclined relative to the first and second mirrors. Each switch cell comprises a switch mirror provided movably relative to the substrate. With this configuration, the path dependence of loss is substantially eliminated.

Optical switch

The present invention is a dispersion compensation device capable of varying dispersion compensation amount with a simple configuration. The device includes a first mode light conversion section capable of converting input light into light of higher mode, a dispersion compensation section capable of performing dispersion compensation on the higher mode light outputted from the first mode light conversion section corresponding to the status of mode of the higher mode light, a second mode light conversion section capable of converting the light of higher mode dispersion-compensated in the dispersion compensation section into light of original mode, and a mode control section capable of variably controlling the status of mode of the higher mode light converted in the first mode light conversion section, and controlling to convert the higher mode light from the dispersion compensation section to the light of original mode in the second mode light conversion section.

Dispersion compensation device

An optical device module includes an optical device with a plurality of electrodes disposed at predetermined positions, a substrate disposed oppositely to the optical device and with wiring patterns for connecting to the electrodes, and a wiring which connects the electrodes to the wiring patterns.

Optical cross-connect apparatus including first wavelength converters converting m different wavelengths &#x3bb;1 through &#x3bb;m contained in n WDM input optical signals into 2m wavelengths &#x3bb;1 through &#x3bb;2m; a first wavelength cross-connector performing cross-connection according to wavelengths, separating the optical signals wavelength-converted by the first wavelength converters into 2m wavelengths combining optical signals with the 2m separated wavelengths; second wavelength converters converting the 2m wavelengths contained in the optical signals cross-connected by the first wavelength cross-connector into 2m wavelengths; a second wavelength cross-connector performing cross-connection according to wavelengths separating the optical signals wavelength-converted by the second wavelength converters into 2m wavelengths and combining optical signals with the 2m separated wavelengths; and third wavelength converters converting the 2m wavelengths &#x3bb;1 through &#x3bb;2m in the optical signals cross-connected by the second wavelength cross-connector into m wavelengths &#x3bb;1 through &#x3bb;m and sending the m wavelengths &#x3bb;1 through &#x3bb;m.

Growing community of inventors

Sapporo, Japan

Yoichi Oikawa