Tunable and highly sensitive temperature sensor based on graphene photonic crystal fiber* *Project supported by the National Natural Science Foundation of China (Grant Nos. 52021006, 52025023, 51991342, and 11888101), the Key R&D Program of Guangdong Province, China (Grant Nos. 2019B010931001, 2020B010189001, and 2018B030327001), the Pearl River Talent Recruitment Program of Guangdong Province, China (Grant No. 2019ZT08C321), the Strategic Priority Research

Abstract

Optical fiber temperature sensors have been widely employed in enormous areas ranging from electric power industry, medical treatment, ocean dynamics to aerospace. Recently, graphene optical fiber temperature sensors attract tremendous attention for their merits of simple structure and direct power detecting ability. However, these sensors based on transfer techniques still have limitations in the relatively low sensitivity or distortion of the transmission characteristics, due to the unsuitable Fermi level of graphene and the destruction of fiber structure, respectively. Here, we propose a tunable and highly sensitive temperature sensor based on graphene photonic crystal fiber (Gr-PCF) with the non-destructive integration of graphene into the holes of PCF. This hybrid structure promises the intact fiber structure and transmission mode, which efficiently enhances the temperature detection ability of graphene. From our simulation, we find that the temperature sensitivity can be electrically tuned over four orders of magnitude and achieve up to ∼ 3.34 × 10−3 dB/(cm⋅°C) when the graphene Fermi level is ∼ 35 meV higher than half the incident photon energy. Additionally, this sensitivity can be further improved by ∼ 10 times through optimizing the PCF structure (such as the fiber hole diameter) to enhance the light–matter interaction. Our results provide a new way for the design of the highly sensitive temperature sensors and broaden applications in all-fiber optoelectronic devices.