Offset Lens Grating Coupler for Photonic Integrated Circuits
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Solution Overview
Problem
Photonic integrated circuits formed as layered structures face challenges in coupling light effectively from optical fiber connectors due to stringent alignment and manufacturing tolerances, as existing methods struggle to efficiently direct light into specific layers.
Innovation Solution
An optical coupling device comprising a lens with an offset central axis and a planar grating that redirects light to relax alignment and manufacturing tolerances, allowing for efficient coupling of light from an optical fiber connector into a waveguide within the photonic integrated circuit, with the grating redirecting the light by an angle less than ninety degrees to improve alignment tolerances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional optical coupling methods are used to direct light from fiber to photonic integrated circuit, then light coupling is achieved, but alignment and manufacturing tolerances become extremely stringent
Solution Approach 1:
The patent introduces a lateral offset between the lens optical axis and the waveguide, creating a new spatial dimension for light coupling. This offset configuration allows light to be coupled into the waveguide from a position and angle that would otherwise be impossible with traditional coaxial alignment, thereby relaxing the stringent alignment tolerances that plague conventional optical coupling methods.
Solution Approach 2:
The patent employs asymmetric positioning where the lens is deliberately offset from the waveguide centerline. This asymmetric configuration creates a specific angled path for light propagation that enables coupling into the waveguide while accommodating larger manufacturing tolerances. The asymmetry transforms the coupling geometry from a tightly constrained coaxial arrangement to a more tolerant offset arrangement.
2Ease of operation
If light is directed orthogonal to layered structure, then light can enter waveguide, but alignment tolerances remain stringent
Solution Approach 1:
The patent creates a dynamic light path where light enters the waveguide at an angle rather than orthogonally. By using the offset lens configuration, the system accommodates a range of incident angles that can still successfully couple light into the waveguide. This angular flexibility dynamically adapts to manufacturing variations, reducing the precision required for alignment compared to fixed orthogonal coupling.
3Productivity
If conventional coupling methods are used, then light transfer is achieved, but coupling efficiency is limited by tight tolerances
Solution Approach 1:
The offset lens is pre-positioned at a specific lateral distance from the waveguide before final assembly. This preliminary configuration establishes an optimal light path geometry that maximizes coupling efficiency while inherently accommodating manufacturing tolerances. The pre-established offset geometry ensures that even with variations in component positioning, the light coupling remains efficient without requiring post-assembly alignment adjustments.
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 enhances the efficiency of light coupling by relaxing alignment and manufacturing tolerances, ensuring precise and effective transfer of light into the photonic integrated circuit, thereby improving the overall performance and reliability of the optical coupling process.
Implementation Method 1
a lens configured to focus the first beam to form a converging second beam
Implementation Method 2
a planar grating configured to redirect the second beam to form a converging third beam
Data Source
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AI summary
Optical coupling device (200) comprising an optical connector (C) delivering light from a source as a first beam (106), a lens (102) having a central axis (104) and focusing the first beam to form a converging second beam (108), the first beam having a central axis (110) that is offset from the lens' central axis (104), the second beam having a central axis that is angled with respect to that of the first beam, a planar grating redirecting the second beam to form a converging third beam, a mirror (202) positioned such that the grating is located between the lens and the mirror and reflecting towards the grating light from the second beam that passes through the grating, and an optical waveguide (W) aligned with the third beam's central axis and receiving the third beam.