Optical Switches with Surface Grating and Edge Couplers
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Solution Overview
Problem
Current photonic integrated circuits (PICs) face challenges in detecting defective optical switches during fabrication, leading to increased fabrication costs and potential customer dissatisfaction due to the inability to test optical switches before the end of the fabrication process, especially since edge couplers can only be formed after wafer division.
Innovation Solution
The implementation of surface grating couplers (SGCs) allows for the testing of optical switches during fabrication, enabling early detection of defects and reducing costs, while also providing edge couplers for post-fabrication testing to ensure quality, and both SGCs and edge couplers enable coupling to fibers at the wafer edge and surface, increasing input and output options.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If edge couplers are used for testing optical switches, then testing can be performed after fabrication, but testing cannot be done during fabrication process
Solution Approach 1:
Surface grating couplers are formed during the fabrication process before the optical switch is completed, enabling preliminary testing of the optical switch at an intermediate stage. This preliminary action allows defect detection to occur during fabrication rather than after completion, reducing rework costs and improving process efficiency.
2Adaptability or versatility
If only edge couplers are used, then post-fabrication testing is possible, but fiber connectivity options are limited
Solution Approach 1:
The optical switch is equipped with both surface grating couplers and edge couplers, making it universally compatible with multiple fiber coupling configurations. Surface grating couplers enable top-surface fiber attachment, while edge couplers provide side-attachment options, giving system designers versatile fiber connectivity choices without requiring separate devices for different applications.
3Productivity
If surface grating couplers are added during fabrication, then early defect detection is enabled, but fabrication process complexity increases
Solution Approach 1:
The formation of surface grating couplers is merged with existing fabrication process steps, specifically utilizing the same lithography and etching sequences already required for other device structures. By combining the SGC formation into the standard fabrication flow rather than adding separate processing steps, the patent enables early defect detection without proportionally increasing fabrication complexity.
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 approach reduces fabrication costs by identifying defective switches early, improves customer satisfaction by ensuring functional products, and enhances PIC functionality with increased fiber connectivity options.
Implementation Method 1
a first input surface grating coupler (SGC) and coupled to the optical switch
Implementation Method 2
a first input edge coupler and coupled to the optical switch
Data Source
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AI summary
A photonic integrated circuit (PIC) (600) comprises an optical switch (650), a plurality of input edge couplers (620) comprising a first input edge coupler (620) and coupled to the optical switch (650), a plurality of input surface grating couplers (SGCs) (630) comprising a first input SGC (630) and coupled to the optical switch (650), a plurality of output edge couplers (620) comprising a first output edge coupler (620) and coupled to the optical switch (650), and a plurality of output SGCs (630) comprising a first output SGC (630) and coupled to the optical switch (650). A method (1100) of fabricating a PIC (600) comprises patterning and etching a silicon substrate to produce a first optical switch (650), a first surface grating coupler (SGC) (630) coupled to the first optical switch (650), and a first edge coupler (620) coupled to the first optical switch (650).