US 4,367,040 AGranted

Multi-channel optical sensing system

AssigneeTokyo Shibaura Denki Kabushiki Kaisha

InventorKenya Goto

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Abstract

A multi-channel optical sensing system for measuring temperature at a number of measuring points includes optical sensors, each of which modulates the incident light beam by light intensity modulation according to the temperature at each measuring point and returns the modulated light beam back to the same optical path. The individual optical sensors are coupled to optical fibers which transmit respective light beams of different wavelengths. These optical fibers are coupled to a wavelength multiplexer/demultiplexer unit, which receives modulated light beams and supplies non-modulated light beams. This unit spectroscopically multiplexes the modulated light beams and spectroscopically demultiplexes the non-modulated light beams. It is optically coupled to another spacially spaced-apart wavelength multiplexer/demultiplexer via an optical system for transmitting light. This other wavelength multiplexer/demultiplexer unit spectroscopically demultiplexes the modulated multiplexed light beam into component light beams supplied to respective other optical fibers and also spectroscopically multiplexes light beams of different wavelengths supplied from the respective other optical fibers. To each of these other optical fibers are coupled a light source unit and modulated light and non-modulated light detecting units.

Claims8

Dependent claims

An optical sensing system comprising;

means for producing unmodulated light beams having different wavelengths;
a plurality of sensors provided at measuring points respectively, the sensors modulating the intensities of said unmodulated light beams in response to physical quantities at the measuring points respectively;
first multiplexing and demultiplexing means for spectroscopically multiplexing the unmodulated light beams having different wavelengths into unmodulated light and spectroscopically demultiplexing modulated light into modulated light beams having different wavelengths;
second multiplexing and demultiplexing means for spectroscopically multiplexing the modulated light beams into modulated light and spectroscopically demultiplexing unmodulated light into the unmodulated light beams;
means for comparing the modulated light beams with the unmodulated light beams generated from said producing means to detect the physical quantities of the measuring points respectively;
a plurality of first optical waveguides which are optically coupled between said first multiplexing and demultiplexing means and said comparing means, through which said modulated and unmodulated light beams are transferred between said first multiplexing and demultiplexing means and said comparing means;
means for transferring the modulated light and the unmodulated light through space between said first multiplexing and demultiplexing means and said second multiplexing and demultiplexing means;
and
a plurality of second optical waveguides which are optically coupled between said second multiplexing and demultiplexing means and said plurality of sensors, through which the modulated and unmodulated light beams are transferred between said second multiplexing and demultiplexing means and sensors.

6 more elements

An optical sensing system comprising;

means for producing unmodulated light beams having different wavelengths;
first multiplexing means for spectroscopically multiplexing the unmodulated light beams into modulated light;
a plurality of first optical waveguides for transferring the unmodulated light beams from said producing means to said first multiplexing means;
first demultiplexing means for spectroscopically demultiplexing the unmodulated light into the unmodulated light beams;
first transferring means for transferring the unmodulated light from said first multiplexing means to said demultiplexing means through space;
a plurality of sensors provided at measuring points respectively, the sensors modulating intensities of the unmodulated light beams with the physical quantities of the measuring points respectively;
a plurality of second optical waveguides for transferring the unmodulated light beams from said first demultiplexing means to said sensors respectively;
second multiplexing means for multiplexing the modulated light beams generated from said sensors into modulated light;
a plurality of third optical waveguides for transferring the modulated light beams from said sensors to said second multiplexing means;
second demultiplexing means for demultiplexing the modulated light into the modulated light beams;
second transferring means for transferring the modulated light from said second multiplexing means to said second demultiplexing means through space;
means for comparing the modulated light beams with the unmodulated light beams generated from said producing means to detect the physical quantities of the measuring points respectively;
and
a plurality of fourth optical waveguides, for transferring the modulated light beams from said second demultiplexing means to said comparing means.

11 more elements

Dependencies are inferred from the claim text.

Facts

Application: 06/152,163Filed 22 May 1980
Priority: JP 54/6639029 May 1979
Granted: 4 Jan 1983
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

G02B 6/2713
As bulk elements, i.e. free space arrangements external to a light guide, e.g. polarising beam splitters: cascade of polarisation selective or…
G02B 6/29308
As bulk element, i.e. free space arrangement external to a light guide: diffractive element having focusing properties, e.g. curved gratings
G02B 6/2931
As bulk element, i.e. free space arrangement external to a light guide: diffractive element operating in reflection
G02B 6/32
Optical coupling means: having lens focusing means positioned between opposed fibre ends