Study on High Temperature Resistant Packaging of Ultra High Temperature Fabry–Perot Optical Fibre Vibration Sensor
Rui Feng, Yao Chu, Zhenjun Liu, Xiaohao Wang, Fei Tang
Abstract
Thermal stress failure is the bottleneck that is restricting the development of ultra-high temperature sensors, and reliable packaging is crucial in their development process. In this paper, a two-step packaging structure was proposed for the high temperature resistant failure packaging challenges of the ultra-high temperature Fabry–Perot optical fibre vibration sensor. First, a high temperature resistant AlN base was selected according to thermal simulation. A reliable bond between the AlN base and the 6H-SiC vibration-sensitive element was designed, which could effectively avoid the failure of thermomechanical stress adaptation during drastic temperature change. In addition, a high temperature resistant ZrO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> support tube with a length of 20 cm, an outer diameter of 16 mm, and an inner diameter of 12 mm was designed as the optical fibre lead-out support structure by using finite element simulation and optimisation. Moreover, the influence of fastening fixtures on the sensor mode was analysed. The simulated first-order resonance frequency of the sensor was 2644.9 Hz, while the actual measurement was 2620 Hz. The difference was only 0.9%. Finally, the validity of the design was verified by experiments, and the sensor achieved reliable operation at 1200 °C.