In the aerospace field, for aerospace engines and other high-end manufacturing equipment working in extreme environments, like ultrahigh temperatures, high pressure, and high-speed airflow, in situ temperature measurement is of great importance for improving the structure design and achieving the health monitoring and the fault diagnosis of critical parts. Optical fiber sensors have the advantages of small size, easy design, corrosion resistance, anti-electromagnetic interference, and the ability to achieve distributed or quasi-distributed sensing and have broad application prospects for temperature sensing in extreme environments. In this review, first, we introduce the current research status of fiber Bragg grating-type and Fabry–Perot interferometer-type high-temperature sensors. Then we review the optical fiber high-temperature sensor encapsulation techniques, including tubular encapsulation, substrate encapsulation, and metal-embedded encapsulation, and discuss the extreme environmental adaptability of different encapsulation structures. Finally, the critical technological issues that need to be solved for the application of optical fiber sensors in extreme environments are discussed.

基于光纤受激布里渊散射的布里渊光纤激光器以其Hz量级甚至亚Hz量级的超窄线宽特性，自问世以来便吸引了广泛的研究关注。超窄线宽布里渊光纤激光器主要经历三个发展阶段，从最初的基于单模光纤谐振腔的布里渊光纤激光器，到向腔内引入掺铒光纤放大器的布里渊掺铒光纤激光器，再到利用一段普通掺铒光纤同时提供布里渊增益与线性增益的紧凑型布里渊掺铒光纤激光器，激光器的性能不断得到发展，相关理论研究也不断得到丰富。近10年，紧凑型布里渊掺铒光纤激光器的研究取得了一系列的进展，在高精度光纤传感等诸多领域有着十分重要的应用前景。按照三个发展阶段依次梳理和总结了布里渊光纤激光器的研究进展，重点阐述了紧凑型布里渊掺铒光纤激光器的机理、特性和应用，并对其未来发展方向进行展望。

In order to meet the practical needs of all-fiber conductivity-temperature-depth sensors with high sensitivity, compact structure, and easy packaging, this Letter uses a microfiber coupler combined with fiber loop (MCFL) reflective photonic device to conduct salinity, temperature, and deep sensing experiments. These MCFLs’ dynamic range and resolution of salinity, temperature, and depth can meet the requirements of actual marine environment monitoring. This structure opens up a new design idea for the practical research of microfiber coupler-based marine environmental parameter sensors.

We modify the pulse-reference-based compensation technique and propose a low-noise and highly stable optical fiber temperature sensor based on a zinc telluride film-coated fiber tip. The system noise is measured to be 0.0005 dB, which makes it possible for the detection of the minor reflectivity change of the film at different temperatures. The temperature sensitivity is 0.0034 dB/°C, so the resolution can achieve 0.2°C. The maximum difference of the temperature output values of the sensor at 20°C at different points in time is 0.39°C. The low cost, ultra-small size, high stability, and good repeatability of the sensor make it a promising temperature sensing device for practical application.