Multi-wavelength Fiber Laser for Interferometric Distance Measurement
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Solution Overview
Problem
Existing interferometric distance measurement devices require multiple laser light sources and complex adjustments, leading to high equipment costs and control complexity, especially when generating multiple wavelengths for accurate distance measurement.
Innovation Solution
A multi-wavelength fiber laser source with integrated Bragg gratings that produces at least three different wavelengths, combined with an interferometer unit and signal processing unit to determine absolute position information, reducing the need for multiple light sources and simplifying control efforts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple separate laser light sources are used to generate multiple wavelengths, then the required wavelengths for interferometric distance measurement are obtained, but the equipment cost and device complexity increase significantly
Solution Approach 1:
The patent combines multiple separate laser light sources into a single fiber laser system that generates multiple wavelengths simultaneously. This is achieved by integrating multiple Bragg gratings with different grating constants into one laser cavity, thereby reducing the number of components and simplifying the overall device structure while maintaining the capability to provide multiple wavelengths for interferometric measurements.
Solution Approach 2:
The fiber laser system is designed to perform multiple functions: it generates multiple wavelengths (at least three) from a single light source, eliminating the need for separate lasers for each wavelength. This multi-functional approach allows one device to replace several individual components, reducing complexity and alignment requirements.
2Measurement precision
If multiple separate laser light sources are used, then the required wavelengths are provided, but the control complexity and stability requirements increase
Solution Approach 1:
By merging the control of multiple wavelengths into a single fiber laser system, the patent reduces the number of independent control channels from three (one for each laser) to one. The single laser source requires only one stability control mechanism, simplifying the control architecture while ensuring wavelength stability for accurate interferometric measurements.
Solution Approach 2:
The patent implements feedback control for the single fiber laser source to maintain wavelength stability. By controlling one light source with feedback mechanisms rather than multiple independent sources, the system achieves the required wavelength stability with reduced control complexity.
3Measurement precision
If multiple laser light sources are used, then multiple wavelengths are generated, but the alignment complexity and adjustment efforts increase
Solution Approach 1:
The patent merges multiple wavelength generation functions into a single fiber laser source, eliminating the need to align multiple separate laser beams. Since all wavelengths originate from one source, the alignment complexity is dramatically reduced, and the interference signal quality is maintained through the inherent coherence of the single-source system.
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 solution significantly reduces equipment costs and control complexity while providing high accuracy and low noise in distance measurements due to the use of a single light source and enhanced coherence length.
Implementation Method 1
at least three different Bragg gratings, whose grating constants are adapted to the generated wavelengths
Implementation Method 2
The measurement and reference beams reflected back from the measurement and reference reflectors interfere, forming an interference beam
Implementation Method 3
A pump light source, at least three Bragg gratings integrated into one or more laser-active fibers
Data Source
Figure 1
Figure 2~3
Figure 4a~4b
AI summary
The present invention relates to a device for interferometric distance measurement. This device comprises a multi-wavelength light source that provides a beam with at least three different wavelengths and is designed as a fiber laser comprising at least three different Bragg gratings whose grating constants are tuned to the generated wavelengths. Furthermore, an interferometer unit is provided that splits the beam into a measurement beam and a reference beam. The measurement beam propagates in a measurement arm towards a measurement reflector and is reflected back there; the reference beam propagates in a reference arm towards a stationary reference reflector and is reflected back there. The measurement and reference beams reflected back from the measurement and reference reflectors interfere to form an interference beam.A detection unit splits the interference beam such that several phase-shifted partial interference signals result for each wavelength. A signal processing unit then uses these partial interference signals of different wavelengths to determine absolute position information relative to the measuring reflector (Fig. 1).