Lens and Grating Coupler for Silicon Photonics Alignment
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Solution Overview
Problem
Silicon photonics face challenges in achieving efficient interface and coupling between high-performance integrated waveguide devices and optical fibers or free-space optics due to high integration density, leading to alignment and coupling efficiency issues.
Innovation Solution
The use of a lens and optical gel to focus light onto a diffraction grating coupler within an optoelectronic integrated chip, allowing for improved coupling efficiency and reduced alignment tolerances, which simplifies packaging and increases testing speed while lowering costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If high integration density is used in silicon photonics, then manufacturing cost and device performance are improved, but alignment and coupling efficiency between waveguides and optical fibers deteriorate
Solution Approach 1:
The patent introduces an optical element (lens or grating coupler) as an intermediary component between the waveguide and optical fiber. This intermediary mediates the coupling process, enabling efficient light transfer while accommodating the misalignment caused by high integration density. The optical element acts as a buffer that transforms the tightly confined waveguide mode into a mode that better matches the optical fiber, thereby resolving the alignment precision problem without sacrificing integration density.
2Productivity
If high integration density is used in silicon photonics, then device performance is improved, but coupling efficiency between waveguides and optical fibers deteriorates
Solution Approach 1:
The patent employs parameter changes by introducing optical elements with specific optical parameters (focal length, grating period, etc.) that are optimized for coupling. The lens focuses light onto the waveguide or the grating coupler diffracts light at specific angles, changing the spatial distribution parameters of light to achieve better mode matching between the waveguide and optical fiber, thereby improving coupling efficiency while maintaining high device performance.
3Loss of energy
If tight coupling is achieved between waveguides and optical fibers, then coupling efficiency is improved, but alignment tolerances become more stringent and packaging complexity increases
Solution Approach 1:
The patent utilizes another dimension by employing grating couplers that operate in the angular domain rather than just the spatial domain. The grating structure diffracts light into specific angular directions, creating a new degree of freedom for coupling. This dimensional change allows for relaxed lateral alignment tolerances because the coupling efficiency becomes less sensitive to lateral displacement when the grating can compensate by adjusting the diffraction angle.
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 solution enhances coupling efficiency between optical fibers and waveguiding layers, reduces fiber light loss, and facilitates low-cost packaging by improving lateral alignment tolerances and focusing capabilities within the silicon photonics system.
Implementation Method 1
The lens is configured to receive, from one of the grating coupler or a light-guiding element, the light beam, and focus the light beam towards another one of the light-guiding element or the grating coupler
Implementation Method 2
The use of a lens and optical gel to focus light onto a diffraction grating coupler within an optoelectronic integrated chip
Implementation Method 3
focus light onto a diffraction grating coupler within an optoelectronic integrated chip
Data Source
AI summary
A device for optical signal processing includes a first layer, a second layer and a waveguiding layer. A lens is disposed within the first layer and adjacent to a surface of the first layer. The second layer is underneath the first layer and adjacent to another surface of the first layer. The waveguiding layer is located underneath the second layer and configured to waveguide a light beam transmitted in the waveguiding layer. A grating coupler is disposed over the waveguiding layer. The lens is configured to receive, from one of the grating coupler or a light-guiding element, the light beam, and focus the light beam towards another one of the light-guiding element or the grating coupler.