Edge Coupler Sealed Cavity Back-End-of-Line Stack
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Solution Overview
Problem
Edge couplers in photonic chips experience significant power losses due to their inability to fully confine incident light modes, primarily because they are smaller than the light sources they receive from, such as lasers or optical fibers.
Innovation Solution
The design incorporates a substrate with a sealed cavity of varying depths, a waveguide core, and a back-end-of-line stack that includes an interlayer dielectric layer and assisting waveguides, which overlap with the sealed cavity to minimize optical signal losses and improve light confinement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the edge coupler size is reduced to integrate optical components, then device integration is improved, but light confinement capability deteriorates
Solution Approach 1:
The patent implements a nested structure where the sealed cavity is positioned within the substrate beneath the waveguide core, and the back-end-of-line stack with assisting waveguides is nested above the waveguide core. This multi-level nesting allows compact integration while maintaining effective light confinement through the layered configuration of substrate-cavity-waveguide-stack.
Solution Approach 2:
The patent transitions from a two-dimensional planar edge coupler to a three-dimensional structure by introducing vertical stacking. The sealed cavity extends vertically within the substrate, and the back-end-of-line stack adds another vertical layer with assisting waveguides, creating a 3D configuration that enhances light confinement without increasing lateral footprint.
2Ease of manufacture
If the edge coupler size is reduced to fit on photonic chip, then manufacturing integration is improved, but light mode confinement deteriorates
Solution Approach 1:
The patent segments the edge coupler into distinct functional modules: the substrate with sealed cavity for mechanical support and initial confinement, the waveguide core for primary light guidance, and the back-end-of-line stack with assisting waveguides for enhanced mode matching. This segmentation allows each component to be optimized independently while maintaining overall integration.
Solution Approach 2:
The patent employs composite structures combining different materials with complementary properties: the substrate material provides mechanical stability, the sealed cavity creates a low-index region for confinement, the waveguide core material guides light efficiently, and the assisting waveguides in the stack provide additional mode matching. This composite approach enables effective light confinement in a compact integrated format.
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
This configuration effectively reduces optical signal losses through the substrate, enhancing the performance of the edge coupler by better confining light modes and improving manufacturability.
Implementation Method 1
the sealed cavity may be used to minimize optical signal losses through the substrate
Implementation Method 2
The assisting waveguide and the waveguide core have an overlapping arrangement with the sealed cavity in the substrate
Data Source
Figure 1A~2A
Figure 2B~3A
Figure 3B~4C
AI summary
An edge coupler (100), comprising a substrate (104), a sealed cavity (116) in the substrate, a waveguide core (130) over the substrate; and a back-end-of-line stack (182) over the waveguide core, the back-end-of-line stack comprises a side edge (184), an interlayer dielectric layer (148), and a first assisting waveguide (152, 154, 156, 158, 168, 170, 172) on the interlayer dielectric layer adjacent to the side edge, and the first assisting waveguide and the waveguide core have an overlapping arrangement with the sealed cavity in the substrate.