▎ 摘　　要

We propose an optical glucose sensor based on an enzymatic graphene oxide (GO)-functionalized pi-phase-shifted long-period fiber grating (PS-LPFG) inscribed on high-birefringence fiber (HBF) by CO2 laser irradiation. To fabricate a sensitive and selective sensor head, we coated the PS-LPFG inscribed on HBF (referred to as the HB-PS-LPFG) with GO and covalently immobilized glucose oxidase (GOD) on the coated GO film. When the enzymatic GO-functionalized HB-PS-LPFG (i.e., the sensor head) is immersed in glucose solution samples, the immobilized GOD catalyzes the oxidation of glucose to gluconic acid, resulting in refractive index (RI) changes in the local sensing region of the fiber. These RI changes lead to variations in the transmission spectrum of the HB-PS-LPFG, and the glucose concentration of the sample can be quantified by measuring spectral shifts. Owing to the birefringence of HBF, the fabricated HB-PS-LPFG had polarization-dependent attenuation dips, which exhibited variations in transmission level or wavelength for both glucose concentration and temperature changes (Delta C and Delta T, respectively). From these attenuation dips, we selected two dips (designated as AD 1 and AD 3) as sensor indicators because they showed linear and independent responses to Delta C in a glucose concentration range of 5 to 25 mM and Delta T in a temperature range of 25 degrees C to 45 degrees C, respectively. The glucose concentration and temperature-induced sensitivities of the two indicators were calculated as similar to 0.0 pm/mM and similar to 86.8 pm/degrees C for AD 1 and similar to 20.8 pm/ mM and similar to 149.2 pm/degrees C for AD 3, respectively, which revealed the sensor capability of simultaneous measurement. With these unique Delta C and Delta T responses of the sensor head, our sensor can detect glucose concentration in a cost-effective way, minimizing the temperature-induced measurement uncertainty. (C) 2021 Society of Photo-Optical Instrumentation Engineers (SPIE)