Temperature Self-Compensation Biosensor Based on LPG Concatenated With SNCS Structure

A biosensor based on long period grating (LPG) concatenated with single-mode-no-core-single-mode (SNCS) fiber structure is designed and demonstrated both theoretically and experimentally. By analyzing the opposite shift of transmission dips formed by LPG and SNCS, the RI and temperature variations can be demodulated to realize the temperature self-compensation. The RI sensitivity of 90.56 nm/RIU is obtained by experiment at 1.333-1.399 with temperature compensation coefficient of -1.33× 10
^-4
/°C. The biosensing performance of the sensor is evaluated by detecting porcine hemoglobin (Hb) solutions with different concentrations and the sensitivity of 0.0165 nm/mg/mL is obtained. The designed sensor with simple structure, high sensitivity, noninvasive and label-free detection capability shows great potential in biosensing applications.