Dainichiseika Color & Chemicals Mfg. Co., Ltd.

National Institute of Advanced Industrial Science and Technology

Trimatiz Limited

Sumitomo Osaka Cement Co., Ltd.

Inter Energy Co., Ltd.

Dainichiseika Color & Chemical

Noriyasu Shiga

Hiroshi Nagaeda

Norio Tanaka

Ichiro Ueno

Takashi Hiraga

Noritaka Yamamoto

Toshiko Mizokuro

Nobutaka Tanigaki

Yoichi Oikawa

Norikazu Miyazaki

Toshio Kataoka

Kaoru Higuma

Shigeru Takarada

Masahito Mure

Shiro Futaki

Hirobumi Watanabe

Masahide Miyachi

Hiroyuki Sato

Yoshiaki Horiuchi

An optical-path-switching apparatus according to the present invention includes a reducing optical system capable of guiding signal light and control light along the direction of gravity into a thermal-lens-forming optical element having an incidence plane positioned to be perpendicular to the direction of gravity in such a way as to differentiate respective convergence points in a direction perpendicular to the optical axis. The apparatus further includes a light-receiving unit configured to converge or condense straight-traveling signal light in the absence of irradiation with the control light and signal light whose optical path has been switched due to irradiation with the control light using the same optical element. Further, the apparatus includes a wedge-type prism provided at a passing position of the optical-path-switched signal light to increase the distance between the optical axis of the optical-path-changed signal light and the optical axis of the straight-traveling signal light.

Optical-path-switching apparatus and light signal optical-path-switching method

An optical deflection apparatus includes a signal light source configured to emit signal light having one or more wavelengths, a control light source configured to emit control light having a wavelength different from the wavelength of the signal light, a thermal lens forming optical element including a light absorption layer configured to transmit the signal light and selectively absorb the control light, and a beam-condensing unit configured to cause beam-condensation of the control light and the signal light at different convergence points in the light absorption layer. The thermal lens forming optical element causes convergence and divergence of the control light and the signal light on an incidence plane of the light absorption layer or its vicinity in a light traveling direction, wherein a thermal lens is reversibly formed in the light absorption layer due to a temperature increase occurring in a region where the control light is absorbed and its peripheral region, and the thermal lens changes a refractive index to change a traveling direction of the signal light.

Optical deflection method and optical deflection apparatus

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

An optical device using an electro-optical element is of great utility value to industry, owing to its fast responsiveness and the like. Prior art has problems such as high cost due to a large number of parts, large device size, and high drive voltage, and it has been a challenge to reduce the number of parts to be used, to downsize the device, and to reduce drive voltage. An optical device of the invention has a reflection structure comprising an input fiberand an output fiberwhich are fastened by a duplex ferrule, a collimating lens, and a reflector elementfor reflecting light. The optical device further comprises a cylindrical lens functioning as a condenser lens, and an electro-optical element, which is placed near a collection point of the condenser lens. Electrodes of the electro-optical elementare configured such that the interelectrode distance becomes smaller the closer they are to the collection part.

Optical device using variable polarization element

A flip-flop circuit of the present invention includes a first switch and a second switch which are connected in series to each other. The first switch includes: two input ports upon which light source light and signal light are incident; two output ports for outputting an optical output; and a thermal lens forming element for forming a thermal lens in a predetermined optical inputting condition. Although the second switch is composed in the same manner as that of the first switch, a relation between the wave-lengths to be utilized is inverted. When a state is changed from OFF to ON, a pulse signal is inputted for setting and one of the rays of output light of the second switch is fed-back to the first switch so as to maintain the state of ON. When the state is changed from ON to OFF, a pulse of additional signal light is inputted. Due to the foregoing, the two states of ON and OFF can be stably maintained.

Optical flip-flop circuit

Growing community of inventors

Ichikawa, Japan

Noriyasu Shiga