Stacked Edge Couplers for Photonic Chip Power Loss Reduction
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Solution Overview
Problem
Conventional edge couplers in photonic chips suffer from significant power losses due to their inability to fully confine incident light modes, resulting from the larger size of light sources compared to the couplers.
Innovation Solution
The implementation of stacked edge couplers, comprising an insulating layer, a waveguide core with a tapered section, and a back-end-of-line stack with assisting waveguides, which are arranged to overlap and minimize light leakage by forming a metamaterial structure that enhances light confinement and coupling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional edge coupler is used, then the structure is simple, but significant power losses occur due to inability to fully confine incident light modes
Solution Approach 1:
The coupler structure is divided into multiple segments: a lower cladding layer, a core layer with tapered section, and an upper cladding layer with back-end-of-line stack. This segmentation allows each layer to perform specific functions for light confinement, reducing power loss while maintaining manageable structural complexity
Solution Approach 2:
The patent introduces a vertical stacking dimension with multiple cladding layers above and below the core, transforming the conventional planar coupler into a three-dimensional structure. This dimensional change enables enhanced light confinement in the vertical direction, significantly reducing power loss
2Loss of energy
If the edge coupler size is increased to match light source size, then light confinement improves, but the coupler becomes larger and more complex
Solution Approach 1:
The core layer features a localized tapered section with varying width, creating different local geometries along its length. This local quality variation enables effective mode matching and light confinement without requiring the entire coupler structure to be enlarged
Solution Approach 2:
The coupler employs composite material layers with different refractive indices (lower cladding, core, upper cladding with varying dielectric materials). This composite structure achieves superior light confinement through refractive index contrast rather than increased physical dimensions
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 stacked edge coupler design effectively minimizes optical signal losses by promoting efficient coupling of light from optical fibers to the waveguide core, reducing diffraction and reflection, and acting as an effective optical material to enhance the overall performance of photonic chips.
Implementation Method 1
The waveguide core is over the first assisting waveguide and includes a tapered section... The second assisting waveguide has an overlapping arrangement with the tapered section of the waveguide core
Implementation Method 2
The stacked edge coupler design effectively minimizes optical signal losses by promoting efficient coupling of light from optical fibers to the waveguide core
Data Source
AI summary
A stacked edge coupler for a photonic chip is provided. The stacked edge coupler includes an insulating layer, a waveguide core, a first assisting waveguide, and a back-end-of-line stack. The first assisting waveguide is on the insulating layer. The waveguide core is over the first assisting waveguide and includes a tapered section. The back-end-of-line stack is over the waveguide core. The back-end-of-line stack includes a side edge, a dielectric layer, and a second assisting waveguide. The second assisting waveguide is on the dielectric layer and arranged adjacent to the side edge. The second assisting waveguide has an overlapping arrangement with the tapered section of the waveguide core.