Nippon Telegraph and Telephone Corporation

Kentaro Honda

Ken Tsuzuki

Hideki Maeda

Takashi Saida

Kotaro Takeda

Ken Ito

Koutaro Takeda

An inter-transmission device connection registration deviceA includes a storage unitthat registers connection information of a case where transponderstoand photo couplerstoas divided various transmission devices are connected through a port o and a port i, a light emission instruction unitthat provides a light emission instruction to the subordinately connected transponders, a transmission/reception detection unitconfigured to detect a light transmission and a light reception at opposing ports o and ibetween transmission devices, e.g., the transponderand the photo couplerin accordance with the light emission instruction, and a registration control unitthat performs a control of registering, in the storage unit, connection information Wof the port o on a light transmission side and the port ion a light reception side that are detected.

Transmission device interconnection registration device, transmission device interconnection registration method, and program

To provide a photodetector that is capable of preventing breakdown caused by electrostatic discharge and with which the breakdown voltage can be expected to enhanced by at least 100 V. In the photodetector of the present invention, a Zener diode made of a germanium and a silicon is connected to a germanium photodiode (GePD). In the photodetector, a silicon substrate, a lower cladding layer, a silicon core layer, and an upper cladding layer provided in the photodiode and the Zener diode are shared by the photodiode and the Zener diode.

Photodetector

An optical modulator that suppresses the chirp due to the mask offset, for example during the phase modulation, and that provides a high waveform quality includes: two RF electrodes for applying one pair of differential signal voltages; at least one fixed potential electrodes for applying a fixed potential; a first conductive semiconductor layer and a second conductive semiconductor layer abutted to the RF electrode or a fixed potential electrode; and a light modulation unit including two optical waveguides branched from one optical waveguide that are arranged along a pn junction unit functioning as a boundary between the first and second conductive semiconductor layers, wherein: the semiconductor layers and the electrode are provided so that the integration amounts of the phase changes caused by the offsets of the positions of the pn junction units in the two optical waveguides from a design value is equal between the two optical waveguides.

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Musashino, Japan

Kentaro Honda