Waveguide Core Phase Matching with Cap Layer
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Solution Overview
Problem
Current photonics chips face challenges in efficiently integrating optical and electronic components due to limitations in waveguide core design, particularly in achieving effective phase matching for polarizers and polarization splitters, which affects signal propagation and mode separation.
Innovation Solution
A structure with a waveguide core having a refractive index that varies with width, combined with a cap layer of different refractive index, is used to achieve phase matching, allowing selective coupling of optical signals and effective mode separation by adjusting the width of the waveguide core sections to match the refractive indices, thereby optimizing signal propagation and reducing insertion loss and cross-talk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the waveguide core width is adjusted to achieve phase matching with the cap layer, then coupling efficiency of optical signals is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent changes the width parameter of the waveguide core to achieve phase matching between the waveguide core and cap layer. By adjusting the width, the effective refractive index of the waveguide core is tuned to match the refractive index of the cap layer, thereby optimizing optical signal coupling efficiency without requiring complex additional structures.
2Adaptability or versatility
If polarizers and polarization splitters are integrated into photonics chips, then functional versatility is improved, but device complexity increases
Solution Approach 1:
The patent implements a unified waveguide core structure that can serve multiple functions: guiding optical signals, acting as a polarizer through anisotropic material properties, and functioning as a polarization splitter by separating TE and TM modes. This multi-functional design eliminates the need for separate discrete components, thereby reducing overall device complexity while maintaining versatility.
Solution Approach 2:
The patent merges the functions of polarizers and polarization splitters into a single integrated waveguide core structure with a cap layer. By combining these optical components into one unified structure, the patent reduces the number of separate elements needed on the photonics chip, simplifying the overall device architecture while preserving all necessary optical functionalities.
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 low insertion loss, low cross-talk, and high extinction ratio in photonics chips, effectively separating and routing different modes of optical signals, enhancing the performance of polarizers and polarization splitters.
Implementation Method 1
The section of the waveguide core has a width that is selected such that the first index of refraction is substantially equal to the second index of refraction to provide phase matching effective for coupling a portion of an optical signal from the waveguide core to the cap layer
Implementation Method 2
The waveguide core has a first index of refraction that varies as a function of width, and the cap layer has a second index of refraction
Data Source
AI summary
Structures including a waveguide core and methods of fabricating a structure including a waveguide core. A back-end-of-line interconnect structure has an interlayer dielectric layer and a cap layer stacked over the interlayer dielectric layer. A waveguide core includes a section arranged beneath the cap layer. The waveguide core has a first index of refraction that varies as a function of width, and the cap layer has a second index of refraction. The section of the waveguide core has a width that is selected such that the first index of refraction is substantially equal to the second index of refraction to provide phase matching effective for coupling a portion of an optical signal from the waveguide core to the cap layer.