Acta Optica Sinica, Vol. 40, Issue 24, 2413001 (2020)
Ultracompact Refractive Index Sensor Based on Integrated Optical Waveguide Trench Coupler
Zhang Chenglong1,2, Cai Chen2, Liu Ke1, Guan Baolu1, and Qi Zhimei2,3,*
- 1Key Laboratory of Opto-Electronics Technology, Ministry of Education, Faculty of Information Technology, Beijing University of Technology, Beijing 100124, China
- 2State Key Laboratory of Transducer Technology, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100190, China
- 3University of Chinese Academy of Sciences, Beijing 100049, China
An ultracompact refractive index sensor based on an integrated optical waveguide trench coupler is proposed herein. The structure includes incident, reflection, and transmission waveguides as well as a submicron-wide trench which is located at the intersection of the incident and the reflection waveguides. The guided wave in the incident waveguide occurs, and the frustrated total internal reflection at the sidewall of the trench makes it so that the light can be partly converted into a transmission wave through evanescent field coupling, while the other partial light will be reflected into the reflection waveguide. The intensity of the transmission light depends on the coupling efficiency of evanescent field, and the reflection light intensity depends on the refractive index of the trench, implying that this integrated optical waveguide trench coupler can be used as a micro/nanosensor for the real-time detection of liquid refractive index or solution concentration. Herein, the new refractive index sensor based on the aluminum nitride rib waveguide is designed and verified via simulation. After the structural optimization, the refractive index sensor has a sensitivity of 207.05%/RIU.
Please Enter Your Email: