Elliptical Silicon Grating Coupler for Laser Mode Matching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional optical grating couplers with circular mode profiles experience significant coupling loss due to mismatch with the non-circular elliptical mode profiles of laser beams, leading to inefficient light coupling in optical transceivers.
Innovation Solution
A silicon optical grating coupler with a wider elliptical mode profile is designed to match the laser beam's mode profile, reducing coupling loss by adjusting its width and shape to better align with the laser's elliptical emission profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional optical grating coupler with circular mode profile is used, then the device structure is simple and easy to manufacture, but significant coupling loss occurs due to mismatch with the elliptical laser beam mode profile
Solution Approach 1:
The patent applies asymmetry by transforming the conventional circular grating structure into an elliptical grating structure. The elliptical grating has different semi-major and semi-minor axes, creating an asymmetric geometry that matches the elliptical mode profile of the laser beam. This asymmetric design enables better mode field matching between the grating and the laser, thereby reducing coupling loss while maintaining manufacturing feasibility through standard photolithography processes.
2Loss of energy
If the grating width is increased to reduce coupling loss, then the mode profile matching improves, but the device area increases
Solution Approach 1:
The patent employs parameter changes by optimizing the elliptical grating's geometric parameters, specifically the semi-major axis and semi-minor axis lengths. Through careful selection of these parameters, the grating achieves optimal mode profile matching with the elliptical laser beam. This parameter optimization allows the grating to reduce coupling loss effectively while controlling the device area, as the elliptical shape provides better coupling efficiency per unit area compared to simply increasing the size of a circular grating.
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 wider silicon optical grating coupler reduces coupling loss by 0.5 decibels to several decibels, improving the efficiency of light coupling by matching the mode profiles, thereby enhancing the performance of optical transceivers.
Implementation Method 1
grating couplers have been used to couple the laser and the lightwave circuits
Data Source
AI summary
A transceiver system may include a laser and a silicon optical grating. The laser may be configured to emit a laser beam at an output of the laser. The laser beam may have a non-circular elliptical mode profile. The silicon grating may be configured to exhibit a mode profile having a shape corresponding to the non-circular elliptical mode profile of the laser beam.