Laser Interferometer Return Light Shielding for Oscillation Stability
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Solution Overview
Problem
Laser interferometers face instability in laser oscillation due to return light, leading to reduced signal-to-noise ratio and measurement accuracy in vibration speed measurements.
Innovation Solution
A laser interferometer design with a shifted optical axis and a light shielding element, which prevents return light from reaching the laser source, stabilizing laser oscillation and improving measurement accuracy by reducing self-mixing coupling and increasing the signal-to-noise ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If return light is allowed to reach the laser source, then the optical path is simplified, but laser oscillation stability deteriorates
Solution Approach 1:
The patent extracts and removes the harmful return light from the optical path by introducing a light shielding element that blocks the return light before it reaches the laser source. This separates the useful light path from the harmful return light path, maintaining system simplicity while eliminating stability issues
Solution Approach 2:
The patent introduces a light shielding element as an intermediary component between the optical modulator and the laser source. This intermediary blocks the return light path without requiring complex optical path changes, thus protecting laser oscillation stability while maintaining a relatively simple overall structure
2Device complexity
If return light reaches the laser source, then the system structure is simpler, but signal-to-noise ratio is reduced
Solution Approach 1:
The patent extracts and removes the harmful return light from the system by positioning a light shielding element to block the return light path. This eliminates the source of interference that degrades the signal-to-noise ratio while keeping the overall system structure relatively simple
Solution Approach 2:
The patent converts the potentially harmful return light into a blocked path, transforming what would be a source of noise and interference into a controlled element. By strategically placing the light shielding element, the system turns the return light problem into an opportunity to improve measurement precision through enhanced signal-to-noise ratio
3Device complexity
If return light interferes with the laser source, then fewer components are needed, but measurement accuracy is reduced
Solution Approach 1:
The patent introduces a light shielding element as a minimal intermediary component that specifically blocks the return light path. This single component addition protects measurement accuracy by preventing return light interference with the laser source, while maintaining relatively simple system architecture
Solution Approach 2:
The patent extracts and removes the harmful effect of return light interference by positioning the light shielding element to block the return path. This eliminates the source of measurement errors that would otherwise degrade vibration speed measurement accuracy without requiring extensive system redesign
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 design effectively prevents return light from interfering with the laser source, enhancing the stability of laser oscillation and measurement accuracy, thereby improving the precision of vibration speed measurements.
Implementation Method 1
an optical modulator configured to modulate the first split light into reference light having a different frequency
Implementation Method 2
object light generated by an object to be measured reflecting the second split light
Implementation Method 3
a first light receiving element configured to receive the third split light; and a second light receiving element disposed at a position different from the first light receiving element and configured to receive the fourth split light
Data Source
AI summary
There is provided a laser interferometer. The laser interferometer includes a laser light source; a first light splitter configured to split the laser light into first split light and second split light; an optical modulator configured to modulate the first split light into reference light from the first split light; a second light splitter configured to split the reference light and object light generated by an object to be measured reflecting the second split light into third split light and fourth split light; a first light receiving element configured to receive the third split light; and a second light receiving element configured to receive the fourth split light. An optical axis of the first split light that travels from the first light splitter toward the optical modulator is shifted from an optical axis of the reference light that travels from the optical modulator toward the first light splitter. A difference between an optical path length from the second light splitter to the first light receiving element and an optical path length from the second light splitter to the second light receiving element is 20 mm or less.