Resin Optical Waveguide Tapered Core for Silicon Photonics
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Solution Overview
Problem
Resin optical waveguides face challenges in reducing transmission loss due to foreign substances, particularly bubbles and resin-derived defects, which are difficult to minimize without increasing manufacturing costs or reducing yield, especially when coupling with silicon optical waveguides where core dimensions and refractive indices differ significantly.
Innovation Solution
The resin optical waveguide design features a core with varying widths along the propagation direction, with specific ranges for maximum and minimum widths, and the absence of large defects or refractive index mismatches at certain sections, optimized for adiabatic coupling with silicon waveguides and connection to single-mode fibers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the core cross-section size is reduced for single-mode waveguide coupling, then coupling efficiency with silicon optical waveguide improves, but positioning accuracy requirements increase significantly
Solution Approach 1:
The patent applies local quality by creating a tapered core structure where the core width varies along the propagation direction. The core has a wider section (first width) at the coupling end and a narrower section (second width) at the fiber connection end. This local variation in core dimensions allows the wider portion to tolerate positioning errors during silicon waveguide coupling while maintaining single-mode operation at the narrower portion for fiber connection.
2Loss of energy
If adiabatic coupling is used between resin and silicon optical waveguides, then light propagation efficiency improves, but core dimension mismatch becomes more critical
Solution Approach 1:
The patent implements dynamics by introducing a gradual transition in core width along the propagation direction through a tapered structure. The core width changes continuously from the first width at the silicon waveguide coupling end to the second width at the fiber connection end, enabling adiabatic mode transformation that reduces reflection and transmission loss while accommodating refractive index differences between materials.
3Reliability
If the core width is increased for adiabatic coupling, then coupling efficiency with silicon waveguide improves, but transmission loss from foreign substances increases
Solution Approach 1:
The patent applies local quality by creating different core width sections at different locations along the propagation direction. The wider core section (first width) is positioned at the silicon waveguide coupling end where high coupling efficiency is needed, while the narrower core section (second width) is positioned at the fiber connection end where the mode field diameter is smaller, thereby reducing the impact of foreign substances and defects on transmission loss.
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 design reduces transmission loss by minimizing the impact of foreign substances and refractive index differences, enabling efficient light propagation with low loss and cost-effective manufacturing for silicon photonics interfaces.
Implementation Method 1
The principle of the resin optical waveguide is that a core and clad(s) that are a combination of a plurality of resins having different refractive indices are combined and the core is used as an optical waveguide
Implementation Method 2
an adiabatic coupling, in which light seeping out in an optical axis direction along the array (also referred to as evanescent light below) is captured and caused to communicate over a predetermined distance in the optical axis direction
Data Source
AI summary
Provided is a resin optical waveguide containing a core, under cladding and over cladding, in which the resin optical waveguide has portions having a core width varying along a light propagation direction, the maximum core width is 4 to 10 μm, and the minimum core width of 1 μm or more and less than 4 μm, when the length of a portion S at which the core width is 1 μm or more and less than 4 μm is LS and the length of a portion at which the core width is 4 to 10 μm is LL, the proportion of LS to the total length is 0.1 to 40%, and the portion S contains neither a certain bubble defect nor a certain defect inside the core and in a vicinity of a core-cladding interface.