Fiber-to-chip grating coupler with segmented periods
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Solution Overview
Problem
Optical gratings used for communication between light sources and other components often exhibit poor coupling efficiency, with a large part of the redirected light not reaching the detector.
Innovation Solution
The development of an efficient fiber-to-chip grating coupler with high coupling efficiency, achieved by improving directionality, increasing optical field overlap, and reducing back reflection through specific grating designs and materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If optical gratings are used to redirect light from optical fiber to chip, then light coupling is enabled, but coupling efficiency is poor with large part of redirected light not reaching the detector
Solution Approach 1:
The grating coupler is divided into multiple sections with different grating periods along the propagation direction. The first section has a first grating period and the second section has a second grating period, allowing progressive redirection of light from shallow to steeper angles, improving coupling efficiency while maintaining directional control
Solution Approach 2:
Different regions of the grating coupler have different local properties - the first section and second section have different grating periods tailored to specific functions. This local variation optimizes the redirection process at each stage, enhancing overall coupling efficiency without compromising the global structure
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 proposed solution significantly enhances the coupling efficiency between optical fibers and chip-based devices, ensuring that a greater percentage of the redirected light is effectively transferred to the detector.
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 light to escape from the other end of the optical gratings
Data Source
AI summary
Disclosed is a system and method for communication using an efficient fiber-to-chip grating coupler with a high coupling efficiency. In one embodiment, a method for communication, includes: transmitting optical signals between a semiconductor photonic die on a substrate and an optical fiber array attached to the substrate using at least one corresponding grating coupler on the semiconductor photonic die, wherein the at least one grating coupler each comprises a plurality of coupling gratings, a waveguide, a cladding layer, a first reflection layer and a second reflection layer, wherein the plurality of coupling gratings each comprises at least one step in a first lateral direction and extends in a second lateral direction, wherein the first and second lateral directions are parallel to a surface of the substrate and perpendicular to each other in a grating plane, wherein the first reflection layers are configured such that the plurality of coupling gratings is disposed between the first reflection layer and the cladding layer, wherein the second reflection layer are configured such that the cladding layer is disposed between the second reflection layer and the waveguide.