Waveguide Escalator Structures for Low-Loss Photonics Chip Routing
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Solution Overview
Problem
Conventional waveguide crossing arrays on photonics chips suffer from significant insertion loss and substrate leakage due to direct crossings of waveguide cores in different levels, leading to adverse consequences like strong light scattering.
Innovation Solution
A structure comprising a first waveguide core with a back-end-of-line stack that includes dielectric layers of varying refractive indices, featuring openings and strategically positioned waveguide cores within these layers to facilitate efficient light transfer between levels while minimizing direct core crossings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If waveguide cores are directly crossed in different levels, then routing complexity is reduced, but insertion loss increases significantly
Solution Approach 1:
The patent introduces waveguide escalators as intermediary structures between waveguide cores in different levels. These escalators act as mediators that enable light transfer without direct crossing, thereby reducing insertion loss while maintaining routing functionality.
Solution Approach 2:
The patent transitions from direct horizontal crossing to vertical stacking with escalators connecting different levels. By utilizing the vertical dimension and introducing intermediate escalator structures, the system achieves low-loss light transfer while maintaining routing complexity at acceptable levels.
2Area of stationary object
If waveguide cores are directly crossed in different levels, then layout area is reduced, but substrate leakage increases
Solution Approach 1:
The waveguide escalators serve as intermediary structures that prevent direct proximity between waveguide cores in different levels. This mediation eliminates the strong light scattering that causes substrate leakage while maintaining compact layout through vertical integration.
3Ease of manufacture
If conventional waveguide crossing arrays are used, then manufacturing simplicity is maintained, but light scattering increases
Solution Approach 1:
The patent segments the direct crossing path into multiple sections: waveguide cores in lower level, waveguide escalators as intermediate structures, and waveguide cores in upper level. This segmentation eliminates continuous direct proximity and reduces light scattering while maintaining manufacturability through standardized fabrication processes.
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 reduces insertion loss and crosstalk, enabling efficient light transfer with low loss and a reduced footprint, promoting flat through-band performance.
Implementation Method 1
the first dielectric layer comprises a first material with a first refractive index, and the second dielectric layer comprises a second material with a second refractive index different from the first refractive index
Implementation Method 2
waveguide escalators that transfer light between the waveguide cores in the lower level and the waveguide cores in the upper level
Data Source
AI summary
Structures for a waveguide escalator and methods of forming such structures. A structure comprises a first waveguide core, and a back-end-of-line stack including a first dielectric layer, a second dielectric layer on the first dielectric layer, an opening in the second dielectric layer, a second waveguide core including a section that overlaps with a section of the first waveguide core, and a plurality of third waveguide cores disposed between the section of the first waveguide core and the section of the second waveguide core. The plurality of third waveguide cores are positioned inside the opening in the second dielectric layer, the first dielectric layer comprises a first material with a first refractive index, and the second dielectric layer comprises a second material with a second refractive index different from the first refractive index.