Laser Interferometer Frequency Modulation Without Diffraction Gratings
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Solution Overview
Problem
Existing laser interferometers face challenges in efficiently modulating laser light frequencies without using diffraction gratings, which increase manufacturing complexity and cost.
Innovation Solution
A laser interferometer design that utilizes a vibration element to modulate laser light frequencies by generating a vibration component intersecting the incident surface, eliminating the need for diffraction gratings, and includes a photodetector, demodulation circuit, and oscillation circuit to process the modulated signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a diffraction grating is combined with a quartz crystal AT vibrator to enable frequency modulation, then the frequency modulation capability is improved, but the manufacturing complexity and cost increase
Solution Approach 1:
The patent extracts and eliminates the diffraction grating component from the optical modulator system. By removing this complex component, the invention achieves frequency modulation using only the quartz crystal AT vibrator, thereby reducing manufacturing complexity and cost while maintaining the essential frequency modulation function.
Solution Approach 2:
The quartz crystal AT vibrator is designed to perform frequency modulation independently without requiring additional components like diffraction gratings. The vibrator's inherent vibration characteristics are sufficient to achieve the desired frequency modulation when properly configured, making the system self-contained and simpler to manufacture.
2Reliability
If a diffraction grating is used in the optical modulator, then the frequency modulation efficiency is improved, but the manufacturing cost increases
Solution Approach 1:
The diffraction grating is completely removed from the optical modulator design. The invention demonstrates that the quartz crystal AT vibrator alone can achieve frequency modulation without this additional component, thereby reducing manufacturing cost while maintaining adequate frequency modulation efficiency through the vibrator's inherent properties.
Solution Approach 2:
The invention replaces the expensive diffraction grating with a simpler, more cost-effective quartz crystal AT vibrator that can achieve the same frequency modulation function. This substitution significantly reduces the manufacturing cost of the optical modulator while maintaining its operational effectiveness.
3Ease of manufacture
If only a quartz crystal AT vibrator is used without a diffraction grating, then the manufacturing simplicity is improved, but the frequency modulation capability deteriorates
Solution Approach 1:
The patent optimizes the vibration parameters of the quartz crystal AT vibrator, including the vibration amplitude, frequency, and orientation, to achieve effective frequency modulation without a diffraction grating. By carefully controlling these parameters, the system maintains frequency modulation capability while enjoying the manufacturing simplicity of having fewer components.
Solution Approach 2:
The invention utilizes the three-dimensional vibration characteristics of the quartz crystal AT vibrator, particularly the thickness-shear vibration mode, to achieve frequency modulation. By exploiting the vibrator's capability to vibrate in multiple dimensions and orientations, the system compensates for the absence of a diffraction grating and maintains effective frequency modulation through the vibrator's spatial vibration patterns.
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 reduces manufacturing difficulty and cost while enhancing the efficiency of frequency modulation, allowing for accurate measurement of displacement and speed without the need for diffraction gratings.
Implementation Method 1
an optical modulator including a vibration element that generates a vibration component in a direction intersecting an incident surface of the first laser light, and configured to modulate the first laser light by using the vibration element
Implementation Method 2
a photodetector configured to receive the second laser light and third laser light that includes a sample signal generated by the first laser light being reflected by an object, and output a light reception signal
Implementation Method 3
an oscillation circuit configured to operate using the vibration element as a signal source and output the reference signal to the demodulation circuit
Data Source
AI summary
A laser interferometer includes: a laser light source configured to emit first laser light; an optical modulator including a vibration element that generates a vibration component in a direction intersecting an incident surface of the first laser light, and configured to modulate the first laser light by using the vibration element to generate second laser light including a modulation signal; a photodetector configured to receive the second laser light and third laser light that includes a sample signal generated by the first laser light being reflected by an object, and output a light reception signal; a demodulation circuit configured to demodulate the sample signal from the light reception signal based on a reference signal; and an oscillation circuit configured to operate using the vibration element as a signal source and output the reference signal to the demodulation circuit.