Multilayer Grating Coupler Structure for Wide-Band Optical Coupling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Traditional single layer grating couplers exhibit poor coupling efficiency, limited bandwidth, and are susceptible to interference and attenuation as semiconductor chips shrink in size and density increases.
Innovation Solution
Implementing a multilayer grating structure with independently designed grating layers having different refractive indices and geometric dimensions to optimize light guidance and reduce energy loss, increasing coupling efficiency and bandwidth while minimizing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional single layer grating couplers are used, then the structure is simple and easy to manufacture, but the coupling efficiency is poor and bandwidth is limited
Solution Approach 1:
The grating coupler is divided into multiple independent grating layers, each with its own grating structure. The first grating layer includes first grating features, and the second grating layer includes second grating features. This segmentation allows each layer to independently contribute to light coupling, thereby improving overall coupling efficiency and bandwidth while managing complexity through modular design
Solution Approach 2:
The invention transitions from a single-layer (2D) grating structure to a multi-layer (3D) grating structure by adding vertical stacking of grating layers. This dimensional change enables light to be coupled through multiple interfaces and paths, significantly enhancing coupling efficiency and bandwidth without sacrificing manufacturability
2Reliability
If single layer grating couplers are used, then manufacturing is easier, but the device is susceptible to interference and attenuation
Solution Approach 1:
The grating coupler is divided into multiple independent grating layers, each with its own grating structure. The first grating layer includes first grating features, and the second grating layer includes second grating features. This segmentation allows each layer to independently contribute to light coupling, thereby improving overall coupling efficiency and bandwidth while managing complexity through modular design
Solution Approach 2:
The invention employs multiple grating layers with different materials and refractive indices. The first grating layer and second grating layer are formed with different material compositions, creating a composite structure that reduces interference and attenuation through material diversity while maintaining manufacturing feasibility
3Productivity
If semiconductor chips are scaled down to increase density, then production efficiency increases and costs decrease, but optical coupling performance deteriorates
Solution Approach 1:
The invention transitions from a single-layer (2D) grating structure to a multi-layer (3D) grating structure by adding vertical stacking of grating layers. This dimensional change enables light to be coupled through multiple interfaces and paths, significantly enhancing coupling efficiency and bandwidth without sacrificing manufacturability
Solution Approach 2:
The invention employs multiple grating layers with different materials and refractive indices. The first grating layer and second grating layer are formed with different material compositions, creating a composite structure that reduces interference and attenuation through material diversity while maintaining manufacturing feasibility
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 multilayer grating couplers achieve high coupling efficiency, wide bandwidth, and improved stability, making them suitable for silicon photonics applications and convenient for wafer-scale testing and low-cost packaging.
Implementation Method 1
Light coupled from one end of the optical gratings that has been traveling transversely through the optical gratings by reflecting off the inner surfaces at shallow angles may be redirected so that it strikes the inner surfaces at a sharper angle that is greater than the critical angle of incidence
Implementation Method 2
redirected so that it strikes the inner surfaces at a sharper angle that is greater than the critical angle of incidence, thus allowing the redirected light to escape from the other end of the optical gratings
Data Source
AI summary
An apparatus for optical coupling according to the present disclosure includes a semiconductor substrate, a reflective layer disposed on the semiconductor substrate, a lower grating layer above the reflective layer, the lower grating layer including a base layer and a lower grating coupler above the base layer, grating teeth of the lower grating coupler facing the semiconductor substrate, and an upper grating layer above the lower grating layer, the upper grating layer including an upper grating coupler and a coating layer above the upper grating coupler, grating teeth of the upper grating layer facing away from the semiconductor substrate.