Waveguide Vertical Insertion Area for Optical Routing
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Solution Overview
Problem
Current integrated circuit coupling systems face challenges in efficiently routing optical signals due to limitations in waveguide crossings, such as loss and crosstalk, which increase chip size and reduce complexity, and existing methods have not provided practical solutions for interfacing optical fibers to planar lightwave circuits (PLCs).
Innovation Solution
The method involves forming a waveguide assembly with a top clad and optical core, using a photoresist pattern with sloped sidewalls to create a recess and optical vertical insertion area with a mirror, horizontal step, and pocket trench, allowing for efficient optical signal routing and reduced chip size through precise etching and reflective material application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If waveguides are routed to the edge of the PLC substrate for coupling, then optical fiber interfacing is achieved, but the chip size increases and complexity is limited
Solution Approach 1:
The patent introduces vertical dimension by etching recesses into the substrate and positioning waveguides at different heights. The first waveguide is positioned at a first height while the second waveguide is positioned at a second height, creating a three-dimensional waveguide structure that reduces the horizontal footprint and allows more waveguides to be routed without increasing chip size.
Solution Approach 2:
The patent segments the waveguide structure by creating multiple waveguides at different heights and positions within the substrate. The first waveguide and second waveguide are separated vertically and horizontally, with each waveguide having its own recess and cladding structure, allowing independent routing and reducing interference between optical paths.
2Adaptability or versatility
If waveguide crossings are increased to route more signals, then more connections are achieved, but loss and crosstalk increase
Solution Approach 1:
The patent uses vertical separation to eliminate crossings. The first waveguide is positioned at a first height and the second waveguide at a second height, allowing optical paths to pass through the same horizontal plane without intersecting. This three-dimensional arrangement enables more connections without requiring waveguide crossings that cause loss and crosstalk.
Solution Approach 2:
The patent applies different cladding structures to different waveguides based on their specific routing requirements. Each waveguide has its own recess and cladding configuration optimized for its particular path, allowing local optimization of optical performance for each connection while maintaining overall system versatility.
3Device complexity
If optical cores are bent with sharp curves to fit chip layout, then routing flexibility is improved, but transmission loss increases
Solution Approach 1:
The patent resolves routing conflicts by using vertical separation instead of sharp horizontal bends. Waveguides are routed at different heights through the substrate, allowing complex routing patterns to be achieved with gentle curves in each layer while maintaining low transmission loss. The vertical dimension provides an additional degree of freedom for routing optimization.
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 enables efficient optical signal routing with minimal loss and increased complexity, allowing for more connections to optical fiber cores and reduced chip size, improving performance and manufacturing efficiency.
Implementation Method 1
forming an optical vertical insertion area, from the clad sidewalls forming the recess, having a pocket trench, a horizontal step, and a mirror with a reflective material selectively applied to a section of the clad sidewalls
Data Source
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Figure 8A~8C
AI summary
A method of manufacture of an integrated circuit coupling system includes: forming a waveguide assembly, having a top clad over an open end of an optical core; forming a first photoresist having a base photoresist pattern shape with sloped photoresist sidewalls tapered down to expose a portion of the top clad; forming a recess having clad sidewalls from the portion of the top clad exposed by the base photoresist pattern shape, the clad sidewalls having a shape replicating a shape of the base photo resist pattern shape; and forming an optical vertical insertion area, from the clad sidewalls forming the recess, having a pocket trench, a horizontal step, and a mirror with a reflective material selectively applied to a section of the clad sidewalls and exposing the open end opposite to the mirror, the horizontal step between the mirror and the pocket trench.