Nippon Telegraph and Telephone Corporation

Nippon Telephone and Telegraph Corporation

Hideki Fukano

Yuichi Akage

Tadashi Saitoh

Takayuki Yamanaka

Takashi Matsuoka

Munehisa Tamura

Hiroki Nakajima

In a semiconductor photo-detector of the present invention, a first semiconductor layer, a second semiconductor layer having, and a photo-absorption part composed of a photo-absorption layer sandwiched between these layers are disposed on a substrate, at least the photo-absorption layer is formed at a position apart inwardly by a finite length from an end surface of the substrate, an end surface of the second semiconductor layer and the substrate or the end surface of the substrate is provided with a light incident facet angled inwardly as it separates from the surface of the second semiconductor or the surface of the substrate. Further, a groove as a guide of an optical waveguide for guiding incident light is disposed opposing the light incident facet, or the substrate end surface at the light incident facet side is protruded by a finite length from a tip part of the light incident facet, or between the optical waveguide and the semiconductor photo-detector is buried in a solid or liquid, or a main reaching area of incident light refracted at an upper layer of the photo-absorption layer is terminated with a substance having a smaller refractive index than the semiconductor layer of photo-absorption region part, or the light incident facet and its vicinity are buried in an organic substance.

Semiconductor photo-detector, semiconductor photo-detection device, and production method thereof

An electrode pad on a semiconductor substrate having a reduced capacitance of an electrode pad portion and allowing control of a characteristic impedance for a practical electrode pad size is provided. A mesa-stripe type optical waveguide formed by stacking an n-InP clad layeran i layerand a p-InP clad layer and p type contact layeris formed on an n-InP substratean insulating material filmhaving a mesa-shaped deposited portionnear the optical waveguide is formed on the n-InP substratean electrodeand wiring electrodesandfor supplying an electrical signal to the optical waveguide are placed on the optical waveguide and the insulating material filmrespectively, and an electrode padis placed on the top surface of the mesa-shaped deposited portionso that the n-InP substrateand the electrode padhave a predetermined interval t(about 17 to 29 &#x3bc;m)

Electrode pad on conductive semiconductor substrate

In an optical modulation device () having an electrical/optical interaction region (), an electrical signal line () is connected to an electrical signal input terminal (), another electrical signal line () is connected to an electrical signal output terminal (), and a reflection control circuit () is connected to the other electrical signal line (). This reflection control circuit () is an impedance element which positively reflects an output electrical signal from the interaction region () of the optical modulation device (). This makes it possible to raise the upper-limiting frequency at which the E/O (Electrical-to-Optical) response characteristic can be improved, and improve the flatness of the frequency characteristic of the E/O response without deteriorating the absolute value of the E/O response.

Optical modulator and optical modulating method

Semiconductor photo-detector, semiconductor photo-detection device, and production methods thereof

In a semiconductor optical modulator of this invention, each quantum-well layer and each barrier layer of a quantum-well structure serving as a light absorption layer are respectively made of InGaAlN (0&#x2266;X, Y&#x2266;1, 0&#x2266;X+Y&#x2266;1) and InGaAlN (0&#x2266;X', Y&#x2032;&#x2266;1, 0&#x2266;X&#x2032;+Y&#x2032;&#x2266;1). An electric field is being generated in the light absorption layer by spontaneous polarization.

Semiconductor optical modulator and laser with optical modulator

A semiconductor photodetection device includes a light incident facet for receiving light from an optical waveguide. Light received at the light incident facet is refracted through a photo-absorption layer to register photonic events. A material may be introduced between the optical waveguide and the light incident facet to improve responsiveness of the device. The light incident facet may be at an angle to the direction of the light emitted from the optical waveguide to cause the incident light to be refracted through several layers of the semiconductor photodetection device.

Growing community of inventors

Tokyo, Japan

Hideki Fukano