SiN Waveguide Polarization Device for High Power
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Solution Overview
Problem
Photonic integrated circuit (PIC) structures with silicon (Si) cores face significant power-dependent loss and integration challenges with high-power photonic devices, such as silicon nitride (SiN) waveguides, due to signal loss and increased area consumption in Si-to-SiN transitions.
Innovation Solution
A PIC structure incorporating a first waveguide with a SiN core and a stacked second waveguide featuring a primary SiN core laterally adjacent and a secondary core stacked vertically to ensure mode matching, with optional tapering for improved performance, allowing easy integration with high-power photonic devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If Si cores are used in polarization devices, then CMOS processing compatibility and small footprint are achieved, but power-dependent loss increases and integration with high-power photonic devices becomes difficult
Solution Approach 1:
The waveguide structure is segmented into different materials: SiN cores for high-power sections and Si sections for polarization device sections. This allows each material to be used in its optimal application domain - SiN for high-power transmission and Si for CMOS-compatible polarization functionality.
Solution Approach 2:
The patent employs composite waveguide structures combining SiN and Si materials. The SiN core provides high-power handling capability while the Si cladding or surrounding structures enable CMOS processing compatibility and polarization device functionality, creating a hybrid material system that leverages the advantages of both materials.
2Adaptability or versatility
If Si-to-SiN transitions are included for integration, then integration with high-power photonic devices is enabled, but signal loss increases and area consumption increases
Solution Approach 1:
Instead of lateral Si-to-SiN transitions that cause mode mismatch and loss, the patent uses vertical stacking of waveguides. The polarization device waveguides are positioned above or below the high-power waveguide sections, allowing integration in the vertical dimension rather than requiring problematic lateral transitions.
Solution Approach 2:
The stacked waveguide configuration acts as an intermediary structure that enables coupling between Si-based polarization devices and SiN-based high-power waveguides without requiring direct lateral transitions. The vertical stacking provides a lossless or low-loss coupling path through the substrate.
3Adaptability or versatility
If Si-to-SiN transitions are included for integration, then integration with high-power photonic devices is enabled, but area consumption increases
Solution Approach 1:
The patent resolves the area consumption issue by moving the integration transition from the lateral plane to the vertical dimension. Stacked waveguides utilize the third dimension (height) for coupling, thereby reducing the footprint area required for Si-to-SiN transitions compared to lateral routing paths.
4Reliability
If stacked waveguide with secondary core is used, then mode matching is ensured, but device complexity increases
Solution Approach 1:
The second waveguide is segmented into multiple functional sections: a primary core for high-power transmission and secondary cores for mode steering and matching. Each segment has a specific function, and the segmentation allows independent optimization of mode matching without compromising the overall high-power transmission capability.
Solution Approach 2:
Different portions of the stacked waveguide have different structural characteristics tailored to local requirements. The secondary cores are positioned specifically to provide mode matching in certain sections, while the primary core maintains uniform structure for high-power transmission, applying local structural quality where needed.
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
The solution provides a robust high-power polarization device that reduces signal loss and area consumption, enabling efficient integration with high-power photonic devices and enhancing performance in high-power applications.
Implementation Method 1
at least one secondary core, which is stacked vertically with the primary core (e.g., above and/or below) to steer the optical mode and ensure mode matching occurs between adjacent first and second coupling sections of the first and second waveguides, respectively
Implementation Method 2
Optionally, the primary and secondary cores of the second waveguide can be tapered to increase the probability that mode matching will occur
Data Source
AI summary
Disclosed is a structure including a polarization device with first and second waveguides. The first waveguide includes a core (e.g., a silicon nitride (SiN) core) suitable for high-power applications. The second waveguide includes: a primary core (e.g., another SiN core), which is positioned laterally adjacent to the core of the first waveguide and suitable for high-power applications, and secondary core(s) stacked vertically with the primary core to steer the optical mode and ensure that mode matching occurs between adjacent first and second coupling sections of the first and second waveguides, respectively, in order to achieve high-power splitter and/or combiner functions. Optionally, the primary and secondary cores of the second waveguide can be tapered at least within the second coupling section to increase the likelihood of mode matching.