MEMS Optical Interferometer Branching-Combining Unit Light Loss
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Solution Overview
Problem
Conventional MEMS-based optical interferometers face challenges with high light loss and low interference efficiency due to numerous interfaces between the branching-combining unit and the surrounding medium, making it difficult to form antireflection films and maintain detection accuracy.
Innovation Solution
The optical interferometer design separates the branching and combining surfaces, using a MEMS-based branching-combining unit with a transparent semiconductor material, and employs optical systems with strategically placed mirrors to adjust optical path differences, minimizing light loss and improving interference efficiency by ensuring coherent light interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a MEMS-based branching-combining unit is used to minimize the interferometer size, then the device can be compact and integrated, but numerous interfaces between the branching-combining unit and surrounding medium cause high light loss
Solution Approach 1:
The patent introduces a dispersion compensating member as an intermediary component between the branching-combining unit and the optical paths. This member compensates for wavelength dispersion caused by the numerous interfaces, thereby reducing the harmful effects of multiple interfaces without increasing the overall device size significantly.
Solution Approach 2:
The patent optimizes the refractive index and thickness parameters of the branching-combining unit and dispersion compensating member to minimize light loss. By carefully selecting and adjusting these parameters, the system reduces reflection losses at multiple interfaces while maintaining compact dimensions.
2Device complexity
If one plane of the branching-combining unit is used for both branching and combining light, then the device structure is simplified, but wavelength dispersion occurs requiring additional dispersion compensating members
Solution Approach 1:
The patent segments the optical functions by using different planes of the branching-combining unit for branching and combining operations. The first principal surface is used for branching incident light into first and second branched light, while the second principal surface is used for combining the branched light. This segmentation eliminates wavelength dispersion without significantly increasing device complexity.
Solution Approach 2:
The patent transitions from using a single plane for both branching and combining to using separate planes (different dimensions of the branching-combining unit). This dimensional separation allows independent optimization of branching and combining functions, eliminating wavelength dispersion while maintaining structural simplicity.
3Loss of information
If different surfaces of the branching-combining unit are used for branching and combining, then wavelength dispersion is decreased, but the device complexity increases
Solution Approach 1:
The patent makes the branching-combining unit multi-functional by using its two principal surfaces for different optical functions. The first principal surface performs branching function while the second principal surface performs combining function. This universal design allows a single component to handle multiple optical tasks, reducing the need for additional separate components and thereby limiting the increase in device complexity.
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 configuration reduces light loss and enhances interference efficiency by optimizing the optical path lengths and beam alignment, allowing for more accurate detection of interference intensity without the need for antireflection films, thus improving the overall performance of the MEMS-based optical interferometer.
Implementation Method 1
An optical interferometer according to one embodiment uses a MEMS-based branching-combining unit to partially reflect incident light on a first principal surface of the branching-combining unit, and transmit the rest of the incident light through the surface
Implementation Method 2
transmit the rest of the incident light through the surface
Implementation Method 3
The first optical system reflects the first branched light output from the branching surface by one or a plurality of mirrors, and directs the reflected first branched light to the incident surface
Implementation Method 4
The second optical system reflects the second branched light output from the output surface by one or a plurality of mirrors, and directs the reflected second branched light to the combining surface
Implementation Method 5
the combining surface combines the first branched light and the second branched light to be output to the outside as combined light
Data Source
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AI summary
An optical interferometer 1A includes a branching-combining unit 10, a first optical system 20, a second optical system 30, and a drive unit 40, which can be MEMS-based components. The branching-combining unit 10 includes a branching surface 11, an incident surface 12, an output surface 13, and a combining surface 14 on an interface between the interior and the exterior of a transparent member. The branching-combining unit 10, on the branching surface 11, partially reflects incident light L0 and outputs as first branched light L11, and transmits the rest of the incident light into the interior as second branched light L21. The branching-combining unit 10, on the combining surface 14, outputs the first branched light L12 to the outside, reflects the second branched light L22, and combines the light beams to be output to the outside as combined light L3. Thus, a MEMS-based optical interferometer capable of decreasing light loss from branching to combining and improving interference efficiency is realized.