Polymer Optical Waveguide Adiabatic Coupling Silicon Photonics
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Solution Overview
Problem
Current polymer optical waveguides used in silicon photonics do not adequately reduce propagation loss between silicon optical waveguides and optical fibers, and they require improvements in productivity and inspectability.
Innovation Solution
A polymer optical waveguide design featuring a core with under-cladding and over-cladding, where the core width and height are optimized to achieve adiabatic coupling with silicon optical waveguides and single-mode optical fibers, with specific refractive index differences and structural features that reduce peeling and bending losses, and enhance inspection capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a polymer optical waveguide uses adiabatic coupling with conventional structure, then coupling with silicon optical waveguide is achieved, but propagation loss between silicon optical waveguide and optical fiber cannot be reduced sufficiently
Solution Approach 1:
The patent applies local quality by creating different core width regions along the light propagation direction. The coupling section has a first core width optimized for adiabatic coupling with silicon optical waveguides, while the optical waveguide section has a second core width optimized for low-loss connection with optical fibers. This spatial variation in core width allows each section to be optimized for its specific function, simultaneously achieving low propagation loss and reliable coupling.
Solution Approach 2:
The patent changes the core width parameter along the light propagation direction to resolve the contradiction. By varying the core width from the coupling section to the optical waveguide section, the waveguide achieves different coupling characteristics at different positions, enabling both adiabatic coupling with silicon waveguides and low-loss connection with optical fibers.
2Productivity
If polymer optical waveguide structure is simplified, then productivity is improved, but inspection capability and manufacturing precision deteriorate
Solution Approach 1:
The patent segments the polymer optical waveguide into distinct functional sections: a coupling section with a first core width for adiabatic coupling, and an optical waveguide section with a second core width for low-loss fiber connection. This segmentation allows each section to be optimized independently for its specific function while maintaining overall manufacturability through standardized fabrication processes.
Solution Approach 2:
The patent introduces a dimensional change by varying the core width along the light propagation direction (z-dimension). This spatial variation in the horizontal dimension allows the waveguide to achieve different functional characteristics without adding vertical complexity, thereby maintaining manufacturing simplicity while improving both productivity and inspection capability through defined geometric features.
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 design achieves low-loss adiabatic coupling with silicon optical waveguides and single-mode optical fibers, improves productivity by preventing core film peeling, and facilitates easy inspection of propagation losses.
Implementation Method 1
an under-cladding 12 that has a refractive index lower than a refractive index of the core 11 and is provided around the core 11; and an over-cladding 13 that has a refractive index lower than the refractive index of the core 11 and is provided around the core 11
Implementation Method 2
a coupling section 14 and an optical waveguide section 15 that are provided along a light propagation direction, the coupling section 14 is a section in which the over-cladding 13 is not provided and the core 11 and the under-cladding 12 around the core 11 are exposed
Implementation Method 3
the polymer optical waveguide includes portions having different core widths along the light propagation direction, and, when a core width at a portion a having a narrowest core width is denoted Wa (μm) and a core height at the portion a is denoted Ha (μm), Ha is 1.3 μm or more and 4.5 μm or less, and Ha/Wa is 1.15 or less
Data Source
AI summary
The present invention relates to a polymer optical waveguide including: a core; an under-cladding; and an over-cladding, in which the polymer optical waveguide includes a coupling section and an optical waveguide section that are provided along a light propagation direction, the polymer optical waveguide includes portions having different core widths along the light propagation direction, and when a core width at a portion a having a narrowest core width is denoted Wa (μm) and a core height at the portion a is denoted Ha (μm), Ha is 1.3 μm or more and 4.5 μm or less, and Ha/Wa is 1.15 or less.