Compact Optical Coupler With Asymmetric Mode Confinement
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Solution Overview
Problem
Conventional optical couplers that rely on mode evolution principles to couple light between tapering waveguides increase in size as the target operating bandwidth increases, requiring long coupler lengths to accurately split light between outputs.
Innovation Solution
The use of asymmetric mode confinement in rib waveguides with varying shoulder heights and widths to facilitate light coupling over a shorter distance, achieved through optical couplers with rib waveguides having shoulders that taper to provide asymmetrical mode confinement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If adiabatic tapers are used to maintain single mode in waveguides, then light splitting accuracy is improved, but coupler length increases
Solution Approach 1:
The waveguide structure employs asymmetric confinement where one waveguide has a wider core region and the other has a narrower core region. This asymmetry creates different effective refractive indices and mode profiles that enhance coupling efficiency while allowing for shorter interaction lengths, thus reducing overall coupler length while maintaining splitting accuracy.
Solution Approach 2:
The invention applies different structural characteristics to different regions of the waveguides. Specifically, the asymmetric waveguides have locally varied core widths and confinement structures in the coupling region compared to the input/output regions. This local differentiation enables enhanced light coupling in the interaction zone without requiring uniformly long waveguide structures throughout.
2Adaptability or versatility
If target operating bandwidth is increased, then operational versatility is improved, but coupler size increases
Solution Approach 1:
The asymmetric waveguide configuration creates a coupling mechanism that is less sensitive to wavelength variations. The differential mode confinement and effective index mismatch in asymmetric waveguides produce a flatter coupling response across a broader wavelength range, enabling wideband operation without proportionally increasing device size.
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 allows for compact optical couplers to achieve target light splitting over a broad operating bandwidth while reducing the overall size compared to traditional couplers.
Implementation Method 1
the first rib waveguide is optically coupled to the second rib waveguide in a central region
Implementation Method 2
The asymmetric confinement may promote the coupling of light between waveguides and may reduce the overall size of the respective optical coupler
Data Source
AI summary
Configurations for an optical coupler that includes waveguides that provide asymmetric mode confinement. The optical coupler may include first and second rib waveguides, and the width of the shoulder of at least one rib waveguide may taper to provide the asymmetric mode confinement. In some instances the shoulders of one or both rib waveguides may have different heights in a central region of the optical coupler.