Bilayer Photonic Y-Splitter SiN Si Integration
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Solution Overview
Problem
The integration of SiN and Si components in photonic devices, such as Mach-Zehnder Interferometers, requires additional transitions, increasing footprint, complexity, and insertion loss due to material mismatch, particularly in 3 dB optical Y-splitters.
Innovation Solution
A bilayer photonic Y-splitter design that combines a SiN waveguide with underlying Si waveguides, featuring a flared and inverse tapered structure, allowing for efficient light transfer from SiN to Si without the need for discrete interlayer transitions, reducing overall length and complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a SiN waveguide is followed by a Si phase shifter, then material mismatch requires additional transition pieces, but this increases footprint, complexity and insertion loss
Solution Approach 1:
The patent merges the SiN waveguide and Si waveguide into a single integrated structure where the Si waveguide is positioned directly beneath the SiN waveguide in a vertical stack. This combining eliminates the need for separate transition pieces by creating a direct interface between the two materials through precise lateral alignment and gap control, thereby reducing device complexity while maintaining material compatibility.
2Reliability
If additional transition pieces are introduced between SiN and Si components, then material mismatch is addressed, but footprint increases
Solution Approach 1:
The patent transitions from a lateral transition approach to a vertical stacking approach. By positioning the Si waveguide directly beneath the SiN waveguide in the vertical dimension and controlling the lateral gap between them, the interface is created without requiring additional horizontal space for transition structures, thereby reducing footprint while maintaining reliable material interfacing.
3Reliability
If discrete interlayer transitions are used, then material mismatch is managed, but insertion loss increases
Solution Approach 1:
The patent creates a homogeneous interface structure by precisely controlling the gap between the SiN and Si waveguides and ensuring lateral alignment. This homogeneous configuration minimizes optical mode mismatch and scattering at the interface, thereby reducing insertion loss while maintaining stable material interfacing through controlled structural uniformity.
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 a compact 3 dB light splitting with reduced insertion loss and increased robustness to fabrication tolerances, eliminating the need for additional transition pieces and enhancing the performance of photonic devices like VOAs and MZIs.
Implementation Method 1
A bilayer photonic Y-splitter design that combines a SiN waveguide with underlying Si waveguides, featuring a flared and inverse tapered structure, allowing for efficient light transfer from SiN to Si
Data Source
AI summary
A photonic Y-splitter includes a substrate, first optical waveguides disposed in the substrate on a first layer, the first optical waveguides may be flared at a first end and inverse tapered toward a second end and may be substantially mirror images of one another, and a second optical waveguide disposed in the substrate on a second layer, above the first layer, the second optical waveguide being centered over the first optical waveguides and longitudinally arranged between the first end and the second end.