Dual-Member Edge Coupler for Polarization-Dependent Loss Mitigation
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Solution Overview
Problem
Modern semiconductor devices face challenges in miniaturizing optical data links due to device size constraints and polarization-dependent loss in edge couplers, which affect light coupling performance.
Innovation Solution
A dual-member edge coupler design is proposed, incorporating two edge coupling members with different coupling designs to optimize transverse electric (TE) and transverse magnetic (TM) modes, along with auxiliary edge couplers to enhance light coupling performance, thereby reducing coupling length and mitigating polarization-dependent loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a single edge coupler design is used, then the device size is reduced, but polarization-dependent loss increases
Solution Approach 1:
The edge coupler is divided into two distinct members: a first edge coupler optimized for TE mode and a second edge coupler optimized for TM mode. Each member has different structural characteristics (e.g., different widths or geometries) to selectively couple specific polarization modes, thereby reducing polarization-dependent loss while maintaining compact device size.
Solution Approach 2:
Different regions of the edge coupler structure are designed with different properties to handle different polarization modes. The first and second edge couplers have locally optimized geometries and dimensions tailored to their respective target modes (TE or TM), enabling each region to perform its specific function optimally within the compact overall structure.
2Volume of moving object
If coupling length is reduced for miniaturization, then device size decreases, but light coupling performance deteriorates
Solution Approach 1:
The edge coupler members feature tapered or varying width profiles along their lengths, creating a dynamic transition in structural properties. This dynamic geometry allows for optimized mode matching and coupling efficiency over shorter interaction lengths, enabling miniaturization without sacrificing coupling performance.
Data Source
AI summary
A method includes: receiving a substrate; and forming an edge coupler on the substrate, the edge coupler configured to receive light. The forming includes: depositing a first edge coupling member extending in a first direction in a first layer over the substrate; and depositing a second edge coupling member extending in the first direction in a second layer over the first layer. Each of the first and second edge coupling members has a width measured in a second direction monotonically non-decreasing in the first direction. One of the first and second edge coupling members includes a portion in a concave shape and the other includes a portion in a convex shape.