Waveguide Crossings with Free Space Gap
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Solution Overview
Problem
Direct waveguide core crossings in photonics chips result in significant insertion loss and high cross-talk due to strong light scattering caused by the close proximity of waveguide cores in different levels.
Innovation Solution
A structure for waveguide crossing is designed with a first waveguide core having sections aligned along a longitudinal axis and a second waveguide core with a longitudinal axis angled relative to the first, allowing the angled axis to cross within a gap, thereby reducing light scattering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If waveguide cores are arranged in multiple levels with direct crossings, then the layout area is reduced and integration is improved, but insertion loss increases and cross-talk increases due to strong light scattering
Solution Approach 1:
The patent transitions from a two-dimensional planar waveguide crossing to a three-dimensional structure by introducing a vertical gap and free space propagation region. The first waveguide core is positioned at a first vertical level and the second waveguide core is positioned at a second vertical level, with the gap providing vertical separation. This dimensional change allows the waveguide cores to cross without direct contact, reducing light scattering while maintaining compact layout area.
2Adaptability or versatility
If waveguide cores are arranged in multiple levels with direct crossings, then the integration of optical components is improved, but cross-talk increases due to strong light scattering
Solution Approach 1:
The patent uses vertical separation to eliminate cross-talk between waveguide cores while maintaining integration. The gap structure with free space propagation region allows optical signals to pass through vertically without interacting with adjacent waveguide cores, preventing cross-talk while enabling multi-level integration of optical components on the photonics chip.
3Device complexity
If waveguide cores are positioned close together in different levels, then the device complexity is reduced, but light scattering increases causing insertion loss
Solution Approach 1:
The patent introduces a gap structure with free space propagation region as an intermediary between the first waveguide core and the second waveguide core. This intermediary structure allows optical signals to transition between vertical levels without direct contact between waveguide cores, reducing light scattering while maintaining relatively simple device complexity through a straightforward gap formation process.
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 proposed structure effectively reduces light scattering and associated losses at waveguide crossings, improving the efficiency and reliability of photonics chip operations.
Implementation Method 1
direct crossings of waveguide cores may result in significant insertion loss and high cross-talk due to strong light scattering induced by the close local proximity of the waveguide cores in the different levels
Data Source
AI summary
Structures for a waveguide crossing and methods of forming such structures. The structure comprises a first waveguide core including a first section, a second section, and a first longitudinal axis. The first section and the second section are aligned along the first longitudinal axis, the first section is terminated by a first end, the second section is terminated by a second end, and the first end of the first section is longitudinally spaced from the second end of the second section by a gap. The structure further comprises a second waveguide core having a second longitudinal axis angled relative to the first longitudinal axis. The second longitudinal axis of the second waveguide core crosses the first longitudinal axis of the first waveguide core within the gap.