BOCDA Sensor Phase Code Modulation for Spatial Resolution
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Solution Overview
Problem
Existing optical fiber Brillouin correlation domain analysis (BOCDA) sensors face challenges in improving detection performance and accuracy due to difficulties in modulating phase code frequencies, varying correlation peak widths, and the need for a delay fiber, which complicates control design and device configuration.
Innovation Solution
The use of independently controlled phase modulators for probe and pumping light to create phase code patterns with a time difference, allowing for adjustable correlation peak positions and bit widths, thereby eliminating the need for optical frequency modulation and simplifying the device configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If phase code frequency modulation is used to control correlation peak position, then detection accuracy can be improved, but device complexity increases due to the need for delay fiber and frequency modulation components
Solution Approach 1:
The patent extracts and eliminates the delay fiber component from the system. Instead of using delay fiber to control correlation peak position, the invention uses independent phase modulators on probe and pump lights to achieve the same function through phase code patterns, thereby simplifying device configuration while maintaining detection accuracy
Solution Approach 2:
The patent replaces the mechanical/optical delay fiber system with an electrical phase modulation system. By using independent phase modulators controlled by electrical signals to generate phase code patterns, the system substitutes complex optical path management with simpler electrical control, reducing device complexity
2Manufacturing precision
If phase code frequency is changed to measure different positions, then spatial resolution can be improved, but control design becomes more difficult
Solution Approach 1:
The patent implements dynamic control of correlation peak position through independent phase modulators that can be adjusted in real-time. By changing phase code patterns dynamically rather than physically reconfiguring optical paths, the system achieves high spatial resolution while maintaining simple control design
Solution Approach 2:
The patent changes phase code parameters (phase codes and time differences) to control correlation peak position and spatial resolution. By adjusting these parameters through electrical control rather than physical reconfiguration, the system achieves flexible spatial resolution with simplified control design
3Reliability
If delay fiber is added to set detection section at second or greater correlation position, then Brillouin amplification can be achieved at desired positions, but device complexity increases
Solution Approach 1:
The patent removes the delay fiber component entirely from the system. Instead of adding delay fiber to achieve Brillouin amplification at desired positions, the invention uses independent phase modulators to control the correlation peak position directly, eliminating the need for delay fiber while maintaining reliable Brillouin amplification
Solution Approach 2:
The patent introduces phase code patterns as an intermediary mechanism between the phase modulators and the Brillouin amplification process. By using phase codes to control correlation peak position, the system achieves precise positioning for Brillouin amplification without requiring physical delay elements
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 enhances spatial resolution and detection accuracy by allowing arbitrary control of correlation peak positions, eliminating the need for a delay fiber and simplifying control designs, thereby improving detection performance and accuracy.
Implementation Method 1
a probe light phase modulator (121) and a pumping light phase modulator (131), which are adapted to be independently controlled, on a probe light optical fiber line (120) and a pumping light optical fiber line (130), respectively, so that a time difference is formed in a phase code pattern created in each of the probe light phase modulator (121) and the pumping light phase modulator (131)
Implementation Method 2
an optical frequency is adjusted so that the optical frequency difference Δν between the pumping and probe light matches the Brillouin frequency shift value v B of the measurement target optical fiber. In this case, the pumping light is energy-converted into probe light due to stimulated Brillouin scattering and the probe light is Brillouin light amplified within the measurement target optical fiber
Data Source
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AI summary
The present invention relates to an optical fiber BOCDA sensor. A purpose of the present invention is to provide an optical fiber BOCDA sensor which uses two phase codes to control a correlation peak position, thereby further simplifying control design and device configuration and improving spatial resolution to enhance a sensing performance and detection accuracy in comparison with the prior art.