In this paper, we designed a two-dimensional photonic crystal measurement nano-sensor with an octagonal ring resonator. This nano-sensor is designed using circular silicon rods in a rectangular lattice with a lattice constant of 820 nm, to detect temperatures from 0 ° C to 540 ° C. Photonic band gap was calculated by PWE method and the sensor operating parameters such as sensitivity, transmission efficiency, and quality factor were calculated by FDTD method. As the temperature increases, the resonance wavelength changes to a higher wavelength. The designed photonic crystal nano-sensor works at the resonance wavelength λ = 1733 nm and with the TE polarization. The maximum transmission efficiency, quality factor, and sensitivity are 100%, 582.66, and 33.33 pm/°C, respectively. This nano temperature sensor, designed to work in the nanoscale, can sense the slightest temperature change, so it is well suited for critical and sensitive nanotechnology systems. تفاصيل المقالة