Frequency Shift Light Modulator with On-Chip Diffraction Grating
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Solution Overview
Problem
Existing frequency shift light modulators and laser Doppler measuring devices face challenges in achieving accurate high-frequency modulation and miniaturization, particularly in the MHz band, due to the limitations of simple resonance drives and lack of efficient high-frequency modulation capabilities.
Innovation Solution
A frequency shift light modulator incorporating a plate-shaped resonator with a diffraction grating and a blazed diffraction grating, which enables efficient high-frequency modulation by utilizing a quartz crystal AT resonator for thickness-shear resonance, combined with a laser Doppler measuring device configuration that includes a light source unit, polarization beam splitter, and a light receiving element, allowing for miniaturization and increased accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a simple resonance drive with high Q value is used, then the oscillation sharpness is improved, but the accuracy and realism of the driving method deteriorates
Solution Approach 1:
The patent changes the driving parameters from simple resonance drive to a more complex drive method that applies multiple frequencies simultaneously. This allows the system to maintain oscillation sharpness while improving driving accuracy by using composite frequency signals rather than a single resonant frequency.
Solution Approach 2:
The patent uses a composite approach by combining multiple frequency components to create a composite drive signal. This composite signaling method enables both sharp oscillation characteristics and accurate control by superimposing multiple frequency waves rather than relying on a single resonant frequency.
2Device complexity
If a simple resonance drive is used, then the device complexity is reduced, but the high-frequency modulation capability in MHz band deteriorates
Solution Approach 1:
The patent introduces dynamic frequency modulation capabilities by enabling the resonator to respond to multiple frequency components. This dynamic approach allows the system to adapt to high-frequency MHz band applications while maintaining manageable device complexity through software-controlled frequency synthesis rather than hardware complexity.
Solution Approach 2:
The patent replaces complex mechanical high-frequency modulation mechanisms with an electrical/optical frequency synthesis approach. By using electronic generation of multi-frequency drive signals, the system achieves high-frequency MHz band capability without requiring complex mechanical structures, thus reducing overall device complexity while enhancing adaptability.
3Device complexity
If conventional frequency shift methods are used, then the device structure is simpler, but the light use efficiency and measurement accuracy deteriorate
Solution Approach 1:
The patent employs mechanical vibration of the diffraction grating through the piezoelectric resonator to achieve frequency shifting of the laser beam. This vibration-based approach improves light use efficiency and measurement accuracy by creating dynamic diffraction patterns that enhance the Doppler shift signal, while keeping the device structure relatively simple through the use of a single resonator element.
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 solution enables miniaturization, increased accuracy, and high-frequency modulation of the frequency shift light modulator and laser Doppler measuring device, effectively addressing the limitations of existing technologies by enhancing light use efficiency and stability.
Implementation Method 1
a piezo element that has a property of being deformed when, for example, a voltage, a magnetization, or the like is applied
Implementation Method 2
a quartz crystal AT resonator that performs thickness-shear resonance in a high frequency region in a MHz band
Implementation Method 3
a diffraction grating that is provided on a surface of the resonator and that includes a plurality of linear grooves arranged periodically
Implementation Method 4
A light Doppler shift is used which is caused by incidence of laser light when a sawtooth wave applied voltage rises
Data Source
AI summary
A frequency shift light modulator includes a resonator and a diffraction grating including a plurality of grooves arranged in parallel in a displacement direction of the resonator, and the diffraction grating is provided on the resonator. By providing the diffraction grating on the resonator, it is easy to realize miniaturization and increase in accuracy of the frequency shift light modulator. Further, it is easy to realize application to a high frequency region in a MHz band, that is, high frequency modulation. It is possible to efficiently obtain an effect based on a combination of the resonator and the diffraction grating.