Chaotic Excitation for Coherent Optical Reflectometry
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Solution Overview
Problem
Coherent optical signals in parameter monitoring systems for downhole applications can produce undesirable effects due to coherence, which affect the accuracy of measurements in optical fiber sensing systems.
Innovation Solution
Chaotic excitation of coherent optical sources is employed to reduce coherence by varying the output of the optical source, generating a chaotically excited optical signal that is transmitted into an optical fiber with sensing locations, and using a processor to estimate parameters from the reflected signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If coherent optical signals are used in parameter monitoring systems, then the desired signal quality and measurement capability are achieved, but coherence-related noise and undesirable effects are produced that reduce measurement accuracy
Solution Approach 1:
The patent applies dynamic modulation to the coherent optical source by chaotically varying its output characteristics (phase, frequency, or amplitude) over time. This dynamic transformation converts a static coherent signal into a time-varying signal where the coherence properties change continuously, thereby reducing the persistent coherence-related noise while preserving the signal's ability to carry measurement information through the optical fiber sensor system
Solution Approach 2:
The patent changes the parameters of the coherent optical signal by applying chaotic modulation that varies phase, frequency, or amplitude according to a chaotic sequence. This parameter transformation maintains the signal's coherence properties necessary for measurement while reducing the harmful coherence noise through temporal variation, effectively decoupling the useful signal characteristics from the harmful noise characteristics
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach mitigates the deleterious effects of coherence, enhancing the accuracy of parameter estimation in downhole monitoring systems by reducing coherence-related noise and improving the reliability of measurements.
Implementation Method 1
transmitting the optical signal from the optical source into an optical fiber
Implementation Method 2
receiving a reflected signal including light reflected from the at least one sensing location
Data Source
AI summary
A method for estimating a parameter includes: transmitting a control signal to a coherent optical source, the control signal configured to chaotically vary an output of the optical source and generate a chaotically excited optical signal; transmitting the optical signal from the optical source into an optical fiber, the optical fiber including at least one sensing location; receiving a reflected signal including light reflected from the at least one sensing location; and estimating a value of the parameter using the reflected signal.