Vertically Stacked Waveguides for Low-Loss Light Transfer
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Solution Overview
Problem
Current photonic integrated circuits face challenges in efficiently transferring light between chips without significant optical losses, limiting the flexibility and compactness of photonic systems.
Innovation Solution
The implementation of multi-chip photonic assemblies with vertically stacked waveguides of different dimensions, utilizing adiabatic tapers and anti-reflection coatings to change the mode of light, allowing efficient light transfer across air gaps or direct contact, thereby reducing optical losses and enabling compact configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If light is transferred between vertically stacked photonic integrated circuits, then system compactness and modularity are improved, but optical losses increase due to mode mismatch and reflection at the interface
Solution Approach 1:
The patent applies parameter changes by varying the vertical dimension of waveguide regions to enable mode transformation. Specifically, waveguide regions have different vertical heights (first vertical dimension vs. second vertical dimension) to change the optical mode profile, allowing efficient coupling between vertically stacked photonic integrated circuits while minimizing optical losses.
Solution Approach 2:
The patent introduces intermediary waveguide regions with intermediate vertical dimensions that act as mediators between waveguides of different heights. These intermediate regions facilitate smooth mode transitions and reduce reflection losses at the interface between vertically stacked circuits.
2Productivity
If waveguides of different vertical dimensions are used to transfer light between layers, then light transfer efficiency is improved, but manufacturing precision requirements increase due to dimensional control needs
Solution Approach 1:
The patent applies local quality by making different portions of the waveguide have different vertical dimensions. Specifically, certain waveguide regions have a first vertical dimension while other regions have a second vertical dimension, allowing localized mode transformation without requiring uniform precision across the entire waveguide structure.
Solution Approach 2:
The patent segments the waveguide into multiple regions with different vertical dimensions (first vertical dimension regions and second vertical dimension regions). This segmentation allows each segment to be optimized for specific functions while reducing the overall manufacturing precision burden compared to requiring uniform dimensions throughout.
3Productivity
If adiabatic tapers are used to change light modes, then coupling efficiency is improved, but device complexity increases due to additional structural elements
Solution Approach 1:
The patent achieves mode transformation through parameter changes in the waveguide vertical dimension rather than requiring separate adiabatic taper structures. By varying the vertical height of waveguide regions, the optical mode is naturally transformed, achieving coupling efficiency without additional complexity from dedicated taper elements.
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 achieves low optical loss and broadband wavelength performance, allowing for flexible and compact photonic system designs with improved modularity and reduced footprint.
Implementation Method 1
the second region includes a first adiabatic taper... the fourth region including a second adiabatic taper... The second region and the fourth region change a mode of light travelling between the first photonic integrated circuit and the second photonic integrated circuit
Implementation Method 2
an anti-reflection coating positioned between the second region and the fourth region
Data Source
AI summary
A multi-chip photonic assembly includes first and second photonic integrated circuits having first and second waveguides vertically stacked such that first vertical dimensions of the first and second waveguides occupy different horizontal planes in the stack. At least one of the first and second waveguides has a region that has a second vertical dimension that is larger than the first vertical dimension and either horizontally overlaps the other waveguide and/or vertically contacts the other waveguide. Light moving through one of the waveguides from the first vertical dimension to the other vertical dimension changes modes vertically so that the light moves from one waveguide to the other.