Simulation study of microring resonator for seawater salinity sensing with weak temperature dependence

¹ Department of Physics, Ocean University of China, Qingdao 266100, P.R. China
² State Key Laboratory of Advanced Optical Communication Systems and Networks, Peking University, Beijing 100871, P.R. China

^a e-mail: wangshanshan@ouc.edu.cn

Received: 21 May 2014
Revised: 15 August 2014
Accepted: 18 August 2014
Published online: 15 October 2014

Abstract

A seawater salinity sensor based on microring resonator with weak temperature dependence is proposed, which is coated by MgF₂ film with positive thermo-optic coefficient. Temperature dependences of the sensor on fiber diameter, probing wavelength and coating thickness are theoretically investigated and ranges of microfiber diameters for weak temperature dependence are obtained. Under the temperature insensitive condition, sensitivity and detection limit of salinity sensing are studied. By optimizing the parameters of the sensing system, salinity sensitivity and detection limit can reach 0.03 nm/‰ and 0.13‰, respectively. The model presented here may be helpful for developing weak temperature dependence sensors for salinity sensing with high sensitivity, low detection limit and miniaturized sizes.