Grating Coupler Index Profile for Lower Back Reflection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Optical gratings exhibit poor coupling efficiency, with a significant portion of redirected light not reaching optical detectors, leading to inefficient communication between light sources and other components.
Innovation Solution
A grating coupler design featuring a core layer with gradually decreasing effective refractive index and optimized hole arrangements in the optical coupling region, combined with adjustable optical fiber angles, to enhance coupling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If optical gratings are used to redirect light from optical fibers to optical detectors, then optical communication between light sources and detectors is enabled, but coupling efficiency is poor with a large part of redirected light not reaching the optical detector
Solution Approach 1:
The patent applies local quality by creating a graded index profile where the refractive index varies continuously through the optical grating structure. Specifically, the refractive index is higher in regions where light intensity is higher and lower where light intensity is lower, allowing different portions of the grating to have different optical properties optimized for their local function in redirecting light.
Solution Approach 2:
The patent changes the refractive index parameter through the optical grating structure to improve coupling efficiency. By implementing a graded index profile rather than a uniform index, the patent optimizes the light redirection process and reduces back reflection, thereby improving the fraction of light that reaches the optical detector.
2Reliability
If optical gratings redirect light from optical fibers, then light can be directed to optical detectors, but back reflection occurs reducing coupling efficiency
Solution Approach 1:
The patent converts the harmful back reflection into a beneficial effect by designing the optical grating to utilize the reflected light for enhanced coupling. The graded index profile is specifically engineered to redirect not only the incident light but also the back-reflected light toward the optical detector, transforming what would normally be a loss into a useful contribution to the overall coupling efficiency.
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
Improves coupling efficiency by reducing back reflection and aligning optical signals optimally, achieving efficiencies up to 50% for wavelengths around 1290 nm.
Implementation Method 1
An effective refractive index of the core layer gradually decrease from a first end of the optical coupling region to a second end of the optical coupling region
Implementation Method 2
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
Implementation Method 3
the redirected light to escape from the other end of the optical gratings
Data Source
AI summary
Disclosed are apparatuses for optical coupling and a system for communication. In one embodiment, an apparatus for optical coupling having an optical coupling region is disclosed. The apparatus for optical coupling includes a substrate and a core layer disposed on the substrate. The core layer includes a plurality of holes located in the optical coupling region. An effective refractive index of the core layer gradually decrease from a first end of the optical coupling region to a second end of the optical coupling region.