Nippon Sheet Glass Company, Limited

Yasunori Arima

Nobuyuki Komaba

Kenichi Nakama

Yukihisa Kusuda

Takashi Tagami

Naoko Hikichi

Hisao Nagata

An optical module can achieve an optical system using a transmission-type diffraction grating for bending the optical path of incident light with a specific wavelength by about 90&#xb0;. A substrate of the transmission-type diffraction grating is mounted at an angle in a range of &#xb1;5&#xb0; with respect to the design incident angle &#x3b1; of the incident light. The optical system can be applied to a light multiplexing/demultiplexing module.

Optical path changing module

A light demultiplexer in which a signal and a noise in each channel may be distinctly separated is provided. The light demultiplexer comprises a light-receiving element array for receiving light beams demultiplexed every wavelength from a wavelength multiplexed light beam and arranged in a straight line. The light-receiving element array includes a plurality of light-receiving elements for monitoring signals, and a plurality of light-receiving elements for monitoring noises. The light-receiving elements for monitoring signals and the light-receiving elements for monitoring noise are alternately arrayed in a straight line the direction thereof is the same as that of the arrangement of the demultiplexed light beams.

Photodetector array and optical branching filter using the array

A light-receiving element array is provided in which the degradation of characteristic thereof due to the crosstalk may be prevented. An n-InP layer, an i-InGaAs layer, and an n-InP layer are stacked on an n-InP substrate. Zn is diffused into the topmost n-InP layer to form a p-type diffused region, resulting in a pin-photodiode. A passivation layer is deposited on the structure to a thickness such that a nonreflective condition is satisfied. On the passivation film, a light-shielding film is provided so as to cover the area between light-receiving elements.

Light receiving element array having isolated pin photodiodes

The present invention provides an epitaxially grown compound semiconductor film having a low density of crystal defects which are generated during the course of crystal growth of a compound semiconductor. The present invention also provides a compound semiconductor multi-layer structure including an n-type InP substrate, an n-type InP buffer layer, an undoped InGaAs light-absorbing layer, and an n-type InP cap layer, the layers being successively grown on the substrate through MOCVD. In the InGaAs layer, the compositional ratio of In/Ga is cyclically varied in a thickness direction (cyclic intervals: 80 nm) so as to fall within a range of &plusmn;2% with respect to a predetermined compositional ratio that establishes lattice matching between InGaAs and InP; specifically, within a range between 0.54/0.46 (i.e., In Ga As) and 0.52/0.48 (i.e., In Ga As)

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Osaka, Japan

Yasunori Arima