Hitachi, Ltd.

Hitachi Cable, Inc.

Shoji Yamada

Satoshi Aoki

Minoru Maeda

Akihiko Takase

Katsuyuki Imoto

Atsushi Takai

Toshiki P Tanaka

Seiichi Onoda

Mitsuo Tanaka

Tsutomu Yoshiya

Yasuo Minai

Shin Kita

A two-way optical transmission system in which a plurality of light signals of wavelengths differing one from another are transmitted through a single optical fiber from one end thereof to the other end and from the other end to the one end. One or more assemblies each including an electrooptic transmitter, a dielectric thin-film filter and a rod lens and one or more assemblies each including a rod lens, a dielectric thin-film filter and an opto-electric receiver are connected to the single optical fiber at both ends thereof, respectively.

Two-way optical transmission system

Disclosed is an optical switch for changing over the mode connecting two optical transmission lines comprising two optical fibers directly to each other and the mode connecting an optical communication device between the two transmission lines. In this optical switch, in order to reduce the insertion loss, first, second, third and fourth optical fibers, each having an optical connector attached to one end, are attached to a substrate so that at least parts of the respective optical fibers are fixed to the substrate, and the ends of the first and second fibers are arranged on the substrate movably so that the end face of the first optical fiber confronts the end faces of the second and third optical fibers and the end face of the second optical fiber confronts the end faces of the first and fourth optical fibers.

Switch for optical transmission lines

An optical measurement system for eliminating the influences of time variations on light sources, transmission lines, photo detectors, etc. The system includes light sources which generate two pulse-shaped optical signals of different light wavelengths with a portion of the optical signals being transmitted to a measuring part in a distant place by a transmission line. In the measuring part, a change of a measured object is converted into a variation in the quantity of transmission of light, and the optical signal subjected to the variation is transmitted to a signal processing portion by a transmission line. The varied optical signal is converted into a first electric signal by a photo detector. Another portion of the optical signals from the light sources is converted into a second electric signal by another photo detector. A signal processing circuit provides a measurement output indicative of the quantity of change of the measured object as a function of at least one ratio of the first and second electric signals.

Optical measurement system

Growing community of inventors

Hachioji, Japan

Shoji Yamada