Waveguide Element With Reversed Crystal Orientation
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Solution Overview
Problem
Current waveguide elements with multiple optical waveguides face challenges in achieving high wavelength conversion efficiency due to phase mismatch and differences in crystal growth rates, leading to inefficient light propagation and wavelength conversion.
Innovation Solution
A waveguide element is designed with two crystal regions, each grown from opposing side surfaces of a recess in a substrate, where the crystal orientations are reversed, allowing for efficient contact and alignment, thereby enhancing phase matching and reducing dislocation density, which improves wavelength conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple optical waveguides are used in a waveguide element, then wavelength conversion capability is improved, but phase mismatch occurs leading to reduced conversion efficiency
Solution Approach 1:
The patent applies inversion by reversing the crystal orientation of alternating waveguides. Instead of all waveguides having the same orientation, adjacent waveguides are oriented in opposite directions, which compensates for phase mismatch and enables efficient wavelength conversion across multiple waveguides.
Solution Approach 2:
The waveguide element is segmented into multiple individual waveguides with alternating orientations. This segmentation allows each waveguide to be optimized independently while collectively achieving high wavelength conversion efficiency through the alternating pattern.
2Ease of manufacture
If crystal regions are grown from a substrate, then waveguide structure is formed, but differences in crystal growth rates lead to misalignment and reduced efficiency
Solution Approach 1:
The patent uses inversion of crystal growth direction by growing crystal regions from opposing side surfaces of a recess. This approach ensures that crystals grow toward each other in opposite orientations, automatically achieving precise alignment at the interface while maintaining the desired alternating polarity pattern.
Solution Approach 2:
The recess structure serves as an intermediary that facilitates controlled crystal growth from both sides. By providing a defined geometric constraint, the recess mediates the growth process to ensure proper alignment and contact between oppositely oriented crystal regions.
3Device complexity
If conventional waveguide structures are used, then device simplicity is maintained, but dislocation density is high leading to light loss
Solution Approach 1:
The patent transitions from conventional planar waveguide growth to three-dimensional growth from opposing side surfaces of a recess. This dimensional change allows crystals to grow inward from both sides, reducing dislocation density at the interface while maintaining structural simplicity and enabling better alignment.
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 achieves high wavelength conversion efficiency by ensuring phase matching and minimizing light loss, enabling effective conversion of visible light to ultraviolet with improved crystal quality and reduced impurity incorporation.
Implementation Method 1
the nonlinear polarizations of the two or more optical waveguides are reversed. The wavelength of the incident light can be converted by the waveguide element
Data Source
AI summary
According to one embodiment, a waveguide element includes a first crystal region, and a second crystal region. The first crystal region extends in a first direction and includes a first nitride semiconductor. The second crystal region extends in the first direction, includes a second nitride semiconductor, and is continuous with the first crystal region. A second direction crosses the first direction. The second direction is from the first crystal region toward the second crystal region. A <0001> direction of the first crystal region is from the first crystal region toward the second crystal region. A <0001> direction of the second crystal region is from the second crystal region toward the first crystal region.