Abstract
In response to the urgent demand for high-sensitivity and rapid-response temperature sensors for monitoring the ocean thermocline, this study proposes a fast-response optical fiber temperature sensor based on the micro-silicon-based Fabry-Perot interferometer structure. Using the multi-physics finite element simulation software, a single-mode optical fiber - silicon pillar - chromium film structure FPI fast-response temperature sensor is proposed, and its performance is simulated. For the optical fiber temperature sensor with a cylindrical silicon cavity of 15 μm thickness and 125 μm diameter, a response time of 0.43 ms is achieved, which is two orders of magnitude faster than that of traditional FBG sensors. The free spectral range of the optical fiber temperature sensor in the 1550 nm region is 23.26 nm, and the temperature sensitivity reaches 84.17 pm/℃. This indicates that the sensor achieves sub-millisecond response while maintaining high sensitivity. Further studies were conducted on the influence of the geometric parameters of the silicon pillar thickness and diameter on the response time of the optical fiber temperature sensor. The results show that when the silicon pillar thickness is reduced from 25 μm to 5 μm, the response time is shortened from 0.58 ms to 0.19 ms; when the diameter is reduced from 125 μm to 25 μm, the response time is shortened from 0.43 ms to 0.20 ms. In conclusion, this miniaturized FPI optical fiber temperature sensor possesses both rapid response and high sensitivity characteristics, which aligns with the development trend of fiberization in marine monitoring. It is expected to play a significant role in the field of marine temperature measurement.