Self-aligning Photonic Device with Etch Stop Recess
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Solution Overview
Problem
The existing methods for coupling photonic devices in photonic integrated circuits (PICs) face challenges in achieving precise alignment due to sensitivity to thickness variations of metallization layers and adhesives, leading to inaccuracies in vertical alignment and increased costs from complex assembly processes.
Innovation Solution
A method is developed where a photonic device with a first waveguide is aligned to couple with a second waveguide using a self-aligning mechanism, where the alignment along one axis coincides with a stop area on a support structure on a substrate, allowing for precise etching and reduced variability in alignment, and the use of etch stops and auxiliary cladding layers to adjust for thickness differences between waveguides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If active alignment and micro-bench attachment are used to couple photonic devices, then coupling efficiency is improved, but device complexity and manufacturing cost increase significantly
Solution Approach 1:
The patent implements self-alignment mechanisms where the photonic device automatically positions itself relative to the waveguide during attachment. The attachment structure includes alignment features that guide the photonic device into the correct position without requiring external active alignment equipment or complex adjustment procedures, thereby simplifying the manufacturing process while maintaining high coupling efficiency
Solution Approach 2:
The patent incorporates pre-formed alignment structures and positioning features during the fabrication process. These preliminary alignment features are built into the attachment structure before the actual coupling occurs, eliminating the need for post-fabrication active alignment and reducing both complexity and cost
2Ease of manufacture
If thickness variations of metallization layers and adhesives are present, then manufacturing ease is improved, but vertical alignment accuracy deteriorates
Solution Approach 1:
The patent introduces an intermediary alignment structure that acts as a reference plane between the photonic device and the waveguide. This intermediary structure compensates for thickness variations in metallization layers and adhesives by providing a stable mechanical reference that ensures accurate vertical alignment regardless of variations in underlying layer thicknesses
Solution Approach 2:
The patent designs the attachment structure with adjustable geometric parameters that can compensate for thickness variations. By changing the dimensions and configuration of the alignment features in the attachment structure, the system maintains accurate vertical alignment even when metallization or adhesive layer thicknesses vary during manufacturing
Data Source
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AI summary
An apparatus (1), comprising a photonic device (100, 300) with at least a first waveguide (100a, 300a) having a light-conducting core (101, 301) bounded by at least one cladding layer (102, 103, 104, 302, 303), further comprising at least a second waveguide (200a, 400a) having a light-conducting core (201) bounded by at least one cladding layer (202, 203, 204, 402, 403), wherein the first waveguide (100a) is aligned to couple with the second waveguide (200a), wherein alignment of the first waveguide (100a) with the second waveguide (200a) with respect to at least one axis C coincides with at least one stop area (121, 321) of the photonic device (100) resting on a stop surface (221, 421) of a corresponding support structure (223, 423) on a substrate (200, 400), whereinthe stop area (121) is a stop in a recess(123) from a surface (120) of the photonic device (100). A method to fabricate an apparatus (1)according to the invention, wherein the recess (123) is formed by etching (111) of the photonic device (100), and/or the support structure (223) is formed by etching (211, 212) of the substrate (200), wherein the etching process (111, 211, 212) is selective with respect to at least one interface between two materials in the photonic device (100) and/or in the substrate (200).