Optimization and Experimental Demonstration of Compact and High-Sensitive Multi-Slotted Bragg grating Waveguide Sensor on SOI Platform

摘要

With the need of more efficient and smaller photonics devices one of the most common platforms for fabrication is silicon on insulator (SOI). To make the whole device smaller one would need to use firstly more compact elements. For example change mach-zehnder interferometers with micro ring resonators (MRRs). To make the element more sensitive to surrounding media influences one needs to modify the waveguide shape. Which is why sub-wavelength grating (SWG) receive much attention lately . To further improve it was combined with multiple slots . However at small radiuses MRRs will have high bend losses so using Bragg gratings (BG) is setup is more suitable. Most recent result on this topic with BGs used phase shift exhibited a high sensitivity of 579 nm/RIU and a length of 67.2 μm . In our research we aimed for more compact BG sensor by adopting a small period count and by using a steep first side lobe of the stop-band for higher sensitivity. The optimal device structures were designed by rigorous 3D FDTD simulation and actual devices were fabricated to demonstrate a record-high sensitivity with compact size.