Photonic Integrated Circuit Layout for Flexible Polarization Handling
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Solution Overview
Problem
High fabrication complexity and sensitivity of InP-based polarization splitters and rotators in photonic integrated circuits (PICs) lead to low chip yields, as CMOS process control is not widely available for these platforms, making it challenging to achieve suitable performance.
Innovation Solution
The PIC design incorporates off-chip polarization handling components and systems, allowing for optical connection at specific fiber-to-chip coupling locations, enabling bypassing on-chip units with off-spec performance, and providing flexible polarization handling solutions ranging from fully on-chip to fully off-chip configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If InP-based polarization splitters and rotators are integrated on-chip for handling both TM and TE modes, then the functional completeness of the PIC is improved, but the fabrication complexity and sensitivity increase, leading to reduced chip yields
Solution Approach 1:
The patent divides the polarization handling function into two separate components: an InP-based polarization splitter and an InP-based polarization rotator. This segmentation allows each component to be optimized independently for its specific function, reducing the overall fabrication complexity while maintaining complete polarization handling capability. The splitter separates TM and TE modes, and the rotator converts TM to TE modes, with each component being less sensitive to process variations than a fully integrated solution would require.
2Ease of operation
If InP-based polarization splitters and rotators are integrated on-chip, then on-chip polarization handling is achieved, but the chip yield decreases due to high sensitivity and process control challenges
Solution Approach 1:
The patent changes the operational parameters of the InP-based components by designing the polarization splitter and rotator with specific geometric parameters and material compositions that reduce their sensitivity to fabrication variations. This allows the components to maintain their polarization handling functionality while being more tolerant of process control limitations, thereby improving chip yield without sacrificing on-chip operation capability.
3Manufacturing precision
If the PIC is optimized for TE modes using confined quantum wells, then the manufacturing precision for TE mode handling is improved, but the performance for TM modes deteriorates, requiring additional polarization conversion components
Solution Approach 1:
The patent introduces an InP-based polarization rotator as an intermediary component that converts TM modes into TE modes. This mediator allows the PIC to leverage its optimized TE mode handling capability while also achieving TM mode functionality. The rotator acts as a bridge between the naturally superior TE mode performance and the required TM mode capability, enabling complete polarization handling without compromising the manufacturing precision achieved for TE modes.
Data Source
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AI summary
The invention relates to a PIC (1) comprising at least three fiber-to-chip coupling locations (2, 3, 4), an InP-based polarization handling unit, at least two optical splitter-combiners (9, 11), at least two optical receivers (5, 7), and a plurality of semiconductor-based optical waveguides. The plurality of semiconductor-based optical waveguides are configured and arranged to optically connect a first fiber-to-chip coupling location (2) with a first optical receiver (5) via a first optical splitter-combiner (9), a second fiber-to-chip coupling location (3) with the at least two optical receivers (5, 7) via the InP-based polarization handling unit and the at least two optical splitter-combiners (9, 11), and a third fiber-to-chip coupling location (4) with a second optical receiver (7) via a second optical splitter-combiner (11). The invention also relates to an opto-electronic system (100) comprising said PIC (1).