Nippon Telegraph and Telephone Corporation

Nippon Telegraph and Telephone Communications

Kazutoshi Kato

Takashi Sakamoto

Kazuto Noguchi

Akira Okada

Morito Matsuoka

Yoshihisa Sakai

Sen-ichi Suzuki

Masahiro Ueno

Tadayuki Imai

Seiji Toyoda

Shogo Yagi

Yoshifumi Muramoto

Kazunori Naganuma

Yuichi Okabe

Jun Miyazu

Masahiro Yuda

Shigeo Ishibashi

Atsuo Kozen

Osaake Nakajima

Sen-Ichi Suzuki

A wavelength swept light source includes a sawtooth waveform as a main waveform and an exponential component of the sawtooth waveform to the controlled voltage of the electro-optic deflector. The controlled voltage is controlled so that, as an oscillation wavelength to be swept is swept towards a longer wavelength side, a change rate of the oscillation wavelength is increased.

Wavelength swept light source

An optical communication equipment comprises shared optical sourcesto be shared by communication nodes, the wavelengths of optical signalsare converted into desired wavelengths &#x3bb;a&#x2013;&#x3bb;d according to the addressed information of the corresponding optical label signalsby using the shared optical sourcesand routed to the addressed communication nodes without being converted into electrical signals by using the wavelength routing function of the cyclic-wavelength arrayed-waveguide grating (AWG). The load of each communication node can be reduced by incorporating the multi-wavelength optical sources, which can be shared among individual communication nodes, into the router. Further, each communication node is provided with an optical gate or the like for returning the optical signal to the communication node from which the optical signal has been transmitted through the routerin order to adjust the transmission time lag between the optical signal and the corresponding optical label signal by the controllers

Optical packet routing network system based on optical label switching technique

An optical communication equipment comprises shared optical sourcesto be shared by communication nodes, the wavelengths of optical signalsare converted into desired wavelengths &#x3bb;a&#x2013;&#x3bb;d according to the addressed information of the corresponding optical label signalsby using the shared optical sources, and routed to the addressed communication nodes without being converted into electrical signals by using the wavelength routing function of the cyclic-wavelength arrayed-waveguide grating (AWG). The load of each communication node can be reduced by incorporating the multi-wavelength optical sources, which can be shared among individual communication nodes, into the router. Further, each communication node is provided with an optical gate or the like for returning the optical signal to the communication node from which the optical signal has been transmitted through the routerin order to adjust the transmission time lag between the optical signal and the corresponding optical label signal by the controllers

An optical communication equipment comprises shared optical sources to be shared by communication nodes , the wavelengths of optical signals are converted into desired wavelengths &lgr; according to the addressed information of the corresponding optical label signals by using the shared optical sources and routed to the addressed communication nodes without being converted into electrical signals by using the wavelength routing function of the cyclic-wavelength arrayed-waveguide grating (AWG) . The load of each communication node can be reduced by incorporating the multi-wavelength optical sources, which can be shared among individual communication nodes, into the router . Further, each communication node is provided with an optical gate or the like for returning the optical signal to the communication node from which the optical signal has been transmitted through the router in order to adjust the transmission time lag between the optical signal and the corresponding optical label signal by the controllers

This semiconductor photodetector includes a photoabsorption layer, an n-type first semiconductor layer, and a p-type second semiconductor layer. The photoabsorption layer comprises an n-type first layer and a p-type second layer formed in contact with the first layer. The first semiconductor layer is arranged on the side of the first layer and has a shorter wavelength at a light absorption edge and a lower refractive index than in the photoabsorption layer. The second semiconductor layer is arranged on the side of the second layer and has a shorter wavelength at a light absorption edge and a lower refractive index than in the photoabsorption layer. When a predetermined reverse bias voltage is applied between the first and second semiconductor layers, the first layer is entirely depleted and the second layer is partially depleted.

Semiconductor photodetector

Growing community of inventors

Isehara, Japan

Kazutoshi Kato