Hitachi, Ltd.

Hitachi Cable, Inc.

Mitsumi Electric Company Ltd.

Kabushikikaisha Watanabeseisakusyo

Onoda, Seiichi

Kabusikikaisha Watanabeseisakusyo

Seiichi Onoda

Masao Yano

Toshiki P Tanaka

Yasumasa Koakutsu

Masao Sumi

Tamio Takeuchi

Tsuneo Suganuma

Junichi Shimizu

Mitsuo Tanaka

Hitoshi Yokono

Minoru Maeda

Katsuyuki Imoto

Koji Ishida

Hideo Arima

Hirayoshi Tanei

Shojiro Kawakami

Takanobu Noro

Masaaki Kusano

Ichiro Ikushima

Shigeo Nishida

Sadahiro Ohyama

Masayuki Nakano

Shoji Yamada

Noriaki Sekine

Jiro Nakano

Kiyohide Miyake

Hideji Matsuura

Noribumi Ishi

Syouji Yamada

Minoru Ikenoue

Yasuo Minai

Keiichi Inoue

Shin Kita

Yasusi Anzo

An optical fiber sensing system carries out accurate measurements while avoiding measurement noise factors. For example, effects of the emission power of a light source, fiber insertion loss, fluctuations in the sensitivity of a photo detector, fluctuations in the amplitude of an amplifier, the loss of optical energy due to bending of an optical fiber, the loss of optical energy due to connecting two or more optical fibers, and gain fluctuations of electric circuitry provided on a platform do not affect measurements. A reflective sensor is connected to an end of an optical fiber connected to a light source. The light source outputs physical measurement light and reflected light coming from the reflective sensor is separated into two beams of light. Information on the physical quantity of a measurement target object is detected on the basis of an intensity ratio of the two beams.

Optical fiber sensing system

A connector comprises a plug and a socket. The plug has a main plug body, a plurality of contact pins projecting from the main plug body and including a contact pin for grounding, and a shielding member surrounding the plurality of contact pins. The socket has a main socket body, a plug receiving part provided on the main socket body for receiving the shielding member, a plurality of contact portions provided within the plug receiving part for making contact with corresponding ones of the plurality of contact pins and including a first contact portion for making contact with the contact pin for grounding, and a second contact portion provided on the main socket body for making contact with the shielding member. The plug is detachably coupled to the socket by inserting the shielding member into the plug receiving part. The first and second contact portions are made of a single contact member.

Connector comprising a plug having a built-in optoelectronic conversion

In a device for coupling optically a light source with an optical transmission path, the present invention interposes an optical transmission path structure at the center of the distance between them in order to improve the optical coupling efficiency. The optical transmission path structure consists of a plurality of light transmitting elements arranged so that the light from the light source is received by the structure as incident light and is sent out therefrom as outgoing light at an outgoing angle which is equal to the angle of incidence. The light transmitting elements are arranged in parallel with the optical path of the light emitted from the light source and according to this arrangement, the system of the present device becomes equivalent to a system in which the positions of the light source are located at points of .+-.l.sub.1 from the light outgoing surface of the optical transmission path structure. When used with an optical fiber, the optical transmission path structure is disposed such that the distance from the light source to one end face of the optical transmission path structure is the same as the distance from the end face of the means for transmitting to the other end face of the optical transmission path structure.

Optical transmission device

An opto-electric transformation connector is provided, which can be used, as if it were an electric connector, without consideration of optical transmission of devices connected therewith, in a connecting system for connecting different devices by means of optical fibers. The connector includes an electronic circuit board, on which not only a light emitting element for transmitting optical signals and a light receiving element for receiving optical signals are disposed, but also a driving circuit for driving the light emitting element and an amplifier circuit for amplifying the light signals received by the light receiving element are mounted.

Active optical connector including an electronic circuit board and an

An optical switch having a small number of optical connections includes a substrate in which are provided a first light path for conducting optical signals and a second light path consisting of a photosensitive element and light emitting element in pairs. An optical fiber cable is interrupted by the substrate, and optical signals in the fiber cable are transmitted through the first light path or intervened by an electrical system through the second light path in response to the switching movement of the substrate.

Optical switch

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

A three-layer structure optical fiber comprises a first transparent dielectric core layer having a relatively high refractive index, a second transparent dielectric intermediate layer having a relatively low refractive index and a third transparent dielectric cladding layer having an intermediate refractive index wherein the parameter of the optical fiber is determined as follows: ##EQU1## where B is the bandwidth of the signal to be transmitted, z is the transmission distance, C is the velocity of light in vacuum, .eta.o is the refractive index of the core layer, q is the ratio of refractive indices between the core layer and second layer, V = normalized frequency, ##EQU2## p is the ratio of refractive index between the core layer and the third layer, and U.sub.11 =2,405.

Optical fiber

In order to expand the product between the transmission length and the transmission bandwidth of an optical fiber for use in the optical communication and to facilitate the connection between the optical fibers, the optical fiber is made of transparent materials of three concentric layers of a core whose refractive index gradually decreases in the radial direction from the center, an intermediate layer which has a uniform refractive index lower than the varying refractive index of the core, and a cladding which has a uniform refractive index substantially equal to the lowest refractive index of the core.

Optical transmission line

In order to make the transmission loss of the lowest order leaky mode over the transmission length 10dB or more, an optical fiber for optical transmission is constructed of a cladding layer whose refractive index is constant, an intermediate layer which has a constant refractive index lower than the refractive index of the cladding layer, and a core whose refractive index is continuously varied so as to be the highest at the central part and to be substantially equal to that of the cladding layer at the peripheral part, and the thickness of the intermediate layer is 0.1-1 times the radius of the core.

An optical wave guide comprises a cylindrical body which is made of a first transparent dielectric, and a second transparent dielectric which is concentrically formed on the outer periphery of the cylindrical body and which has an index of refraction lower than that of the first dielectric, the central part of the wave guide being hollow.

Optical wave guide

Growing community of inventors

Tokorozawa, Japan

Seiichi Onoda