Light-Coupling Device with Waveguide Element for Flexible Alignment
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Solution Overview
Problem
Existing light-coupling devices face challenges in achieving high coupling efficiency and flexibility in positioning, particularly when the light-emitting surface of a waveguide is located at the edge of an optical chip, as they require complex and costly manufacturing processes to improve coupling efficiency, and are prone to misalignment issues.
Innovation Solution
A light-coupling device comprising an interposer, an optical chip with a waveguide layer, an optical waveguide element, and a fiber array connector, where the optical waveguide element includes a light-transmitting and light-reflective layer with distinct refractive indices, and a tilted or concave mirror surface for total reflection, allowing the light beam to be vertically reflected and coupled into a fiber array, with a passive alignment method using locating slots and holes for precise positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a grating coupler is used to couple light from fiber to waveguide, then the device can be disposed at any position on the chip and is more tolerable to fiber misalignment, but the coupling efficiency is generally lower than an edge coupler
Solution Approach 1:
The patent introduces an optical waveguide element as an intermediary component between the edge coupler and the fiber array connector. This element includes a light-transmitting layer and a light-reflective layer that work together to redirect the light beam from horizontal propagation in the waveguide to vertical coupling into the fiber, enabling flexible positioning while maintaining high coupling efficiency
Solution Approach 2:
The patent changes the dimension of light beam propagation by using total internal reflection at the interface between the light-transmitting layer and light-reflective layer. The light beam is redirected from horizontal propagation (in the waveguide plane) to vertical propagation (toward the fiber array connector), solving the positioning flexibility problem while maintaining coupling efficiency
2Reliability
If a metal reflective layer is plated on the chip surface to improve coupling efficiency, then the coupling efficiency increases, but the chip thickness must be decreased and the manufacturing complexity and cost increase
Solution Approach 1:
The patent uses a composite structure consisting of a light-transmitting layer and a light-reflective layer with distinct refractive indices. This composite material approach enables total internal reflection at their interface, achieving high coupling efficiency without requiring metal plating or reduced chip thickness, thereby avoiding increased manufacturing complexity
Solution Approach 2:
The patent replaces the mechanical approach of metal reflective layer plating with an optical approach using total internal reflection at the interface between two dielectric layers. This substitution eliminates the need for complex metal deposition processes and chip thinning, reducing manufacturing complexity while maintaining high coupling efficiency
3Adaptability or versatility
If the light-emitting surface of the waveguide is located at the edge of the optical chip, then the waveguide can be integrated with the chip, but other elements may be located on the light-transmission path making direct fiber coupling impossible
Solution Approach 1:
The patent segments the light coupling function into two distinct parts: the edge coupler that interfaces with the waveguide at the chip edge, and the fiber array connector that interfaces with the fiber array. The optical waveguide element acts as an intermediate segment that bridges these two parts, allowing each component to be optimized for its specific function while maintaining overall system integration
Solution Approach 2:
The optical waveguide element serves as an intermediary component that mediates between the edge coupler and the fiber array connector. It receives the light beam from the edge coupler, redirects it through total internal reflection, and delivers it to the fiber array connector, enabling integration flexibility while maintaining alignment ease through the passive alignment mechanism
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 coupling efficiency, reduces assembly time and complexity, and increases manufacturing efficiency and product yield by allowing the light-coupling device to be placed at any position on the chip, effectively altering the light beam's path for improved alignment and flexibility in circuit layout.
Implementation Method 1
a light beam emitted horizontally from the light-emitting surface entering the optical waveguide element through the incident surface, being totally reflected through the reflective surface, and being output as a parallel light beam in the vertical direction through the emergent surface
Implementation Method 2
the light beam being emitted from the emergent surface and entering the optical waveguide lens, being totally reflected through the tilted reflective surface and being coupled to the fibers in the horizontal direction
Data Source
AI summary
A light-coupling device includes an interposer, an optical chip, an optical waveguide element and a fiber array connector. The optical chip includes a waveguide layer with a light-emitting surface located aside the optical chip. The optical waveguide element includes an incident surface facing the light-emitting surface, an emergent surface located atop, and a reflective surface located inside. A light beam emitted horizontally from the light-emitting surface enters the optical waveguide element through the incident surface, totally reflected through the reflective surface and is output as a parallel light beam in the vertical direction through the emergent surface. The fiber array connector includes an optical waveguide lens and a plurality of fibers. The optical waveguide lens faces the emergent surface. One of both horizontal sides of the optical waveguide lens is a tilted reflective surface while the other is a light-coupling surface aligned with the fibers. The light beam is emitted from the emergent surface and enters the optical waveguide lens, totally reflected through the tilted reflective surface, and coupled to the fibers in the horizontal direction.