Photonic integrated circuit and opto-electronic system comprising the same
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Solution Overview
Problem
InP-based PICs face challenges in achieving suitable chip yields due to the high fabrication complexity and sensitivity of polarization splitters and rotators, which are not well-suited for CMOS process control, leading to off-spec performance and scrap rates.
Innovation Solution
A PIC design with three fiber-to-chip coupling locations, an InP-based polarization handling unit, and optical splitter-combiners, allowing for on-chip and off-chip polarization handling components to be integrated, enabling flexible use of on-chip and off-chip polarization handling units based on performance, thus improving chip yields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If InP-based polarization splitters and rotators are integrated on-chip to enable coherent reception, then polarization handling capability is improved, but fabrication complexity and sensitivity increase leading to reduced chip yield
Solution Approach 1:
The PIC is designed with multiple independent fiber-to-chip coupling locations (at least three) that can be independently connected to optical receivers. This segmentation allows the system to bypass problematic polarization handling components while maintaining functional coherence through alternative optical paths using splitter-combiners and waveguides.
Solution Approach 2:
The PIC incorporates universal optical coupling interfaces and splitter-combiner components that can handle optical signals regardless of polarization state. This multi-functionality allows the same optical paths to work with or without the InP-based polarization handling unit, accommodating variations in component performance and enabling flexible system configuration.
2Manufacturing precision
If InP-based polarization handling components are used to separate TM and TE modes, then coherent reception performance is improved, but fabrication sensitivity increases making CMOS process control difficult
Solution Approach 1:
The invention introduces off-chip polarization handling components as intermediary elements between the PIC and the optical receivers. These external components perform the polarization separation function, allowing the on-chip InP-based components to be bypassed when their performance is off-spec, thereby reducing the impact of fabrication sensitivity while maintaining the required polarization handling capability.
Solution Approach 2:
The system is designed with dynamic configurability through multiple coupling locations and optical paths. The polarization handling approach can be dynamically adjusted between on-chip and off-chip solutions based on the actual performance of the fabricated components, allowing optimization of both manufacturing ease and precision.
3Adaptability or versatility
If multiple polarization handling components are integrated on a single die, then device functionality is improved, but device complexity increases
Solution Approach 1:
The PIC architecture is segmented into modular functional blocks: fiber-to-chip coupling locations, optical splitter-combiners, waveguide networks, and polarization handling options. This modular segmentation reduces structural complexity by allowing each component to be independently designed, fabricated, and optimized without requiring complex integration of all functions on a single monolithic structure.
4Area of stationary object
If on-chip polarization handling components are used, then chip footprint is reduced, but component sensitivity to fabrication variations increases
Solution Approach 1:
Off-chip polarization handling components serve as mediators that can be introduced when on-chip components show performance variations. This approach maintains a compact chip footprint for the core PIC functions while allowing external components to compensate for fabrication variations, thereby maintaining reliability without significantly increasing the overall system footprint.
Solution Approach 2:
The design incorporates redundant optical paths and multiple coupling locations as a form of beforehand cushioning. If the on-chip polarization handling components turn out to be off-spec after fabrication, the system can be reconfigured to use alternative paths with off-chip components, cushioning against the risk of performance inconsistency without requiring complete redesign.
Data Source
AI summary
A PIC having at least three fiber-to-chip coupling locations, an InP-based polarization handling unit, at least two optical splitter-combiners, at least two optical receivers, 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 with a first optical receiver via a first optical splitter-combiner, a second fiber-to-chip coupling location with the at least two optical receivers via the InP-based polarization handling unit and the at least two optical splitter-combiners, and a third fiber-to-chip coupling location with a second optical receiver via a second optical splitter-combiner. An opto-electronic system including said PIC.