3D Funnel Photonic Structure for Fiber Waveguide Coupling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The mass production and commercialization of integrated nanophotonic devices are hindered by the lack of a robust, passive, and misalignment-tolerant process for packaging the coupling of light in and out of these devices, due to significant mode mismatch between optical fibers and nanophotonic waveguides, leading to tradeoffs between efficiency, bandwidth, and alignment tolerance in existing techniques.
Innovation Solution
A funnel coupler with a tapered orifice is used to mechanically support and guide an optical fiber to a coupling end, where it can be optically coupled with a waveguide, allowing for high efficiency, high bandwidth, and high alignment tolerance through a 3D photonic structure that minimizes misalignment and uses materials like polymers or silicon, enabling passive and scalable integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If end-fire coupling techniques are used, then bandwidth and efficiency are improved, but alignment tolerance deteriorates (requires ~1 μm precision)
Solution Approach 1:
The patent introduces an intermediary structure (funnel coupler or lens assembly) between the optical fiber and the nanophotonic waveguide. This intermediary component transforms the optical mode from the fiber to match the waveguide mode, acting as a mediator that resolves the mode mismatch problem. The funnel coupler's tapered geometry or the lens's focal properties enable this mode transformation, allowing efficient coupling without requiring sub-micron alignment precision.
Solution Approach 2:
The patent employs parameter changes by varying the geometry of the coupling structure (funnel angle, lens focal length, or mode field diameter) to optimize the coupling conditions. By adjusting these parameters, the system achieves both high efficiency and relaxed alignment tolerance, resolving the contradiction between the two performance metrics.
2Manufacturing precision
If grating couplers are used, then alignment tolerance is improved, but bandwidth and efficiency deteriorate (narrow bandwidth, complex fabrication)
Solution Approach 1:
The patent uses an intermediary coupling structure (funnel or lens) that provides both alignment tolerance and high efficiency simultaneously. Unlike grating couplers that rely on diffraction, this intermediary uses geometric optics or adiabatic mode transformation to achieve coupling, maintaining broad bandwidth while providing relaxed alignment tolerance through the funnel's large aperture or lens's focal properties.
3Reliability
If active alignment tools are used, then coupling efficiency is improved, but device complexity and cost increase
Solution Approach 1:
The patent implements self-service alignment through the funnel coupler's or lens's inherent geometric properties. The tapered funnel structure or lens assembly automatically guides and positions the optical fiber during insertion, enabling passive alignment without requiring active alignment tools. This self-aligning mechanism simplifies the packaging process and reduces complexity while maintaining high coupling efficiency.
4Reliability
If mode matching between fiber and waveguide is achieved, then coupling efficiency is improved, but alignment tolerance deteriorates
Solution Approach 1:
The patent transitions from two-dimensional planar coupling (as in grating couplers) to three-dimensional volumetric coupling using funnel structures or lens assemblies. This dimensional change allows the system to achieve mode matching through the third dimension (depth/length of the funnel or lens), thereby maintaining alignment tolerance in the lateral dimensions while achieving efficient coupling.
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 achieves average excess coupling loss of only 0.05 dB between a single mode fiber and a high confinement silicon waveguide, with alignment tolerance beyond 10 μm, addressing the limitations of current methods and enabling mass production of integrated photonic devices with reduced packaging costs and complexity.
Implementation Method 1
One or more of the funnel coupler or the waveguide can be configured to optically couple the optical fiber and the waveguide
Data Source
AI summary
An optical apparatus for coupling an optical fiber to a waveguide is disclosed. The optical apparatus can comprise a funnel coupler having an orifice configured to receive an optical fiber. The funnel coupler can mechanically support the optical fiber when received in the orifice. The funnel coupler can guide the optical fiber to a coupling end of the funnel coupler and a waveguide disposed adjacent the coupling end of the funnel coupler. One or more of the funnel coupler or the waveguide can be configured to optically couple the optical fiber and the waveguide when the optical fiber is received in the orifice.