Optical sensing arrangements with wavelength and time-displacement detection
First Claim
1. An optical sensing arrangement comprising two laser light sources for producing simultaneous optical pulse signals of two different wavelengths, in which these optical pulse signals are combined by optical coupler means and transmitted over a plurality of discrete optical fibre paths of different lengths terminated by respective sensors for sensing certain parameters at predetermined locations, and in which time-displaced return signals at different wavelengths received over the optical fibre paths from the respective sensors are fed to a single receiver, said receiver including means utilizing the intensity of signals of one of said two wavelengths as a reference basis for correctively determining intensity of signals at the other of said two wavelengths in order to compensate for unknown losses when providing an indication of measurand(s) at the location of the optical sensors.
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Accused Products
Abstract
A two-wavelength referencing optical sensing arrangement comprises two laser sources for producing simultaneous optical pulse signals of two different wavelengths for transmission over a plurality of discrete optical fibre paths to the sensors terminating such paths. Time-displaced return signals of different wavelengths received over the optical paths from sensors are fed into a single receiver which uses the intensity of signals of one wavelength in order to compensate for unknown losses in the system when indicating measurement of conditions sensed at the locations of the optical sensors.
9 Citations
3 Claims
- 1. An optical sensing arrangement comprising two laser light sources for producing simultaneous optical pulse signals of two different wavelengths, in which these optical pulse signals are combined by optical coupler means and transmitted over a plurality of discrete optical fibre paths of different lengths terminated by respective sensors for sensing certain parameters at predetermined locations, and in which time-displaced return signals at different wavelengths received over the optical fibre paths from the respective sensors are fed to a single receiver, said receiver including means utilizing the intensity of signals of one of said two wavelengths as a reference basis for correctively determining intensity of signals at the other of said two wavelengths in order to compensate for unknown losses when providing an indication of measurand(s) at the location of the optical sensors.
Specification