Waveguide Mirror Structure for Vibration-Resistant Optical Scanning
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Solution Overview
Problem
Conventional optical scanning devices are complex and prone to vibration, with optical phased arrays requiring intricate wiring for two-dimensional scanning, which complicates the structure and limits scanning range.
Innovation Solution
A waveguide element with a pair of opposed mirrors and an optical waveguide layer, where one mirror has higher transmittance, allowing light emission and direction control through refractive index, thickness, or wavelength adjustments, enabling simple and robust one-dimensional and two-dimensional scanning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional optical scanning devices use driving units for rotating mirrors, then optical scanning can be performed, but the structure becomes complex and the device becomes prone to vibration
Solution Approach 1:
The patent replaces the mechanical mirror rotation system with an optical phased array that uses phase shifters to control light direction. Instead of physically moving mirrors, the system uses phase modulation of light waves to achieve scanning, eliminating mechanical components and their associated vibrations while simplifying the overall structure.
Solution Approach 2:
The patent changes the control parameter from mechanical angle to optical phase. By adjusting the phase of light at different antenna elements, the scanning function is achieved through parameter modulation rather than physical movement, reducing structural complexity and improving vibration resistance.
2Adaptability or versatility
If optical phased arrays use intricate wiring for two-dimensional scanning, then scanning range can be increased, but the structure becomes more complex
Solution Approach 1:
The patent implements a two-dimensional array of antenna elements where each element can independently control phase and amplitude. This universal configuration allows the same structure to achieve scanning in multiple directions and patterns without requiring additional specialized wiring for different scanning modes, maintaining versatility while controlling complexity.
Solution Approach 2:
The patent transitions from one-dimensional linear arrays to two-dimensional planar arrays of antenna elements. This dimensional expansion enables broader scanning coverage and improved beamforming capabilities while distributing the complexity across a two-dimensional geometry rather than requiring intricate wiring in a single dimension.
3Reliability
If waveguide thickness is increased, then light guidance is improved, but emission control becomes more difficult
Solution Approach 1:
The patent adjusts the waveguide layer thickness to a specific range (50-200 nm) that optimizes both light guidance and emission control. By precisely controlling this geometric parameter, the system achieves effective light confinement for guidance while maintaining sufficient evanescent field coupling for controlled emission, resolving the trade-off between these two functions.
Solution Approach 2:
The patent creates different functional regions along the waveguide structure. The waveguide portion has optimized thickness for light guidance, while the emission region uses controlled coupling to adjacent waveguides or free space. This local differentiation allows each region to be optimized for its specific function without compromising the other.
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 allows for efficient two-dimensional scanning with a simpler structure, reducing complexity and enhancing robustness against vibration, while maintaining high scanning precision.
Implementation Method 1
an optical waveguide layer sandwiched between the two mirrors
Implementation Method 2
a grating whose refractive index varies with period p
Implementation Method 3
allowing light emission and direction control through refractive index, thickness, or wavelength adjustments
Data Source
Figure 1~2
Figure 3~4A
Figure 4B~5
AI summary
An optical device includes a first waveguide that propagates light in a first direction; and a second waveguide including a first mirror, a second mirror, and an optical waveguide layer. The first mirror extends in the first direction and has a first reflecting surface parallel to the first direction and a second direction intersecting the first direction, and the second mirror extends in the first direction and has a second reflecting surface facing the first reflecting surface. The optical waveguide layer is located between the first mirror and the second mirror and propagates the light in the first direction. A forward end portion of the first waveguide is disposed inside the optical waveguide layer. In a region in which the first waveguide and the second waveguide overlap each other when viewed in a direction perpendicular to the first reflecting surface, at least part of the first waveguide and/or at least part of the second waveguide includes at least one grating whose refractive index varies periodically in the first direction.