Fiber Interferometer with Broadband Source for Low-Noise Multiplexing
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Solution Overview
Problem
Existing fiber interferometer measurement systems suffer from moderate signal noise ratios and require multiple lasers to measure changes in fiber length, leading to optical dispersion effects and laser wavelength instability.
Innovation Solution
A fiber interferometer system using a broadband light source and a 3 x 3 interferometer with overlapping reflectors to convert light into interferometric signals, enabling simultaneous measurement of fiber length changes with improved sensitivity and reduced noise, allowing multiplexing without additional lasers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple narrow linewidth lasers operating at mutually different wavelengths are used to measure fiber length changes, then measurement capability for multiple reflectors is improved, but signal noise ratio deteriorates due to optical dispersion effects and laser wavelength instability
Solution Approach 1:
The patent changes the fundamental parameter of the light source from narrow linewidth lasers to a broadband light source with continuous spectrum. This parameter change eliminates optical dispersion effects and laser wavelength instability, achieving a noise floor of roughly -103 dB rad/√Hz while maintaining the capability to measure multiple reflector pairs through wavelength domain multiplexing within the broadband spectrum
Solution Approach 2:
The broadband light source serves multiple functions simultaneously: it provides illumination for multiple reflector pairs across different wavelengths, enables wavelength domain multiplexing, and achieves high signal-to-noise ratio without requiring multiple separate laser sources. This universal light source replaces what would traditionally require multiple specialized narrow linewidth lasers
2Adaptability or versatility
If multiple narrow linewidth lasers are used to interrogate reflectors at different wavelengths, then multiplexing ability is improved, but device complexity increases due to requiring additional lasers for each wavelength
Solution Approach 1:
A single broadband light source performs the work of multiple narrow linewidth lasers, providing illumination across the entire spectral range needed for interrogating multiple reflector pairs. This eliminates the need for multiple separate laser sources and their associated control systems, significantly reducing device complexity while maintaining full multiplexing capability
Solution Approach 2:
The patent merges multiple separate laser sources into a single broadband light source that covers all required wavelengths simultaneously. This consolidation combines the functions of multiple devices into one, reducing system complexity while enabling wavelength domain multiplexing of multiple reflector pairs within the broadband spectrum
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
The system achieves a significantly improved signal-to-noise ratio of -103 dB rad / Hz and enables accurate, high-precision measurements of multiple reflector pairs with reduced noise and optical dispersion, facilitating multiplexing capabilities.
Implementation Method 1
the lead fiber is associated with the excitation light source for being illuminated by said excitation light source
Implementation Method 2
a detection 3 x 3 interferometer associated with the lead fiber for converting light received from the pair of integrated optical reflectors into an interferometric signal
Implementation Method 3
a lead fiber provided with a pair of integrated optical reflectors, such as FBGs with overlapping reflection spectrum
Data Source
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AI summary
The invention relates to an fiber interferometer measurement system for measuring a change in a fiber length. The system comprises a broadband type excitation light source, and a lead fiber provided with a pair of integrated optical reflectors with overlapping reflection spectrum, such as FBGs, defining a sensing fiber section therebetween having a variable fiber length. The lead fiber is associated with the excitation light source for being illuminated by said excitation light source. Further, the system comprises a detection 3 × 3 interferometer associated with the lead fiber for converting light received from the pair of integrated optical reflectors into an interferometric signal.