Multi-wavelength time domain reflectometer
First Claim
1. In an optical sensing system, in which optical pulse outputs of different wavelengths are launched at a launch end into optical fiber means through which returned optical signals are conducted for respective detection at the different wavelengths at the launch end with respect to time by one receiver indicating intensity levels of said returned optical signals corresponding to a parameter being measured, a method of continuously calibrating the receiver, including the steps of:
- extracting level reference signals directly from the respective optical pulse outputs at the different wavelengths; and
feeding back into the receiver said level reference signals varying in accordance with the relative intensity levels of the optical pulse outputs at the different wavelengths being launched into the optical fiber means so that the receiver provides an accurate indication of the parameter being measured.
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Accused Products
Abstract
An optical time domain reflectometry system in which laser level reference signals are derived from the respective laser outputs from the laser sources and fed into a single receiver provided for receiving the back-scattered or returned light along an optical fibre. The receiver is thus continuously calibrated in accordance with the relative intensities of the optical signals at different frequencies being launched into the optical fibre so that the receiver provides an accurate measurement of temperature or other parameter being measured by the system.
21 Citations
7 Claims
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1. In an optical sensing system, in which optical pulse outputs of different wavelengths are launched at a launch end into optical fiber means through which returned optical signals are conducted for respective detection at the different wavelengths at the launch end with respect to time by one receiver indicating intensity levels of said returned optical signals corresponding to a parameter being measured, a method of continuously calibrating the receiver, including the steps of:
- extracting level reference signals directly from the respective optical pulse outputs at the different wavelengths; and
feeding back into the receiver said level reference signals varying in accordance with the relative intensity levels of the optical pulse outputs at the different wavelengths being launched into the optical fiber means so that the receiver provides an accurate indication of the parameter being measured. - View Dependent Claims (2, 3, 4, 5, 6, 7)
- extracting level reference signals directly from the respective optical pulse outputs at the different wavelengths; and
Specification