We present a hybrid-octagonal-photonic-crystal-fiber (HOPCF)-based glucose sensor, in which the core is circular and cladding is octagonal including elliptical holes that are filled with glucose as a sensing material. The proposed HOPCF-based glucose sensor is analyzed applying the finite element techniques with a PML (perfectly-matched-layer) boundary from 1.2 \(\mu\) m to 1.8 \(\mu\) m wavelength range. The sensor performance parameters depend on the glucose concentration, operating wavelength, temperature of the sensing element, and the radius of the core, respectively. We find that when the temperature of the sensing element or radius of the core increases, the key sensor performance parameter, especially the sensitivity, decreases. Moreover, the proposed sensor shows 81.81% relative sensitivity, 0.183 \(\times\) 10 \(^{-8}\) dB/m of confinement loss, 2.44 \(\times\) 10 \(^{-2}\) birefringence, 13.69 \(\mu\) m \(^{2}\) effective area, and 7.798 w \(^{-1}\) km \(^{-1}\) non-linear co-efficient at 1.55 \(\mu\) m of wavelength, respectively. Our proposed HOPCF-based glucose sensor offers a comparatively high sensitivity, moderate birefringence, and low confinement loss while these sensor performance parameters are glucose concentration, temperature, wavelength, and core radius dependent.
