Fiber Bragg grating (FBG) is the most widely used optical fiber sensor due to its compact size, high sensitivity, and easiness for multiplexing. Conventional FBGs fabricated by using an ultraviolet (UV) laser phase-mask method require the sensitization of the optical fiber and could not be used at high temperatures. Recently, the fabrication of FBGs by using a femtosecond laser has attracted extensive interests due to its excellent flexibility in creating FBGs array or special FBGs with complex spectra. The femtosecond laser could also be used for inscribing various FBGs on almost all fiber types, even fibers without any photosensitivity. Such femtosecond-laser-induced FBGs exhibit excellent thermal stability, which is suitable for sensing in harsh environment. In this review, we present the historical developments and recent advances in the fabrication technologies and sensing applications of femtosecond-laser-inscribed FBGs. Firstly, the mechanism of femtosecond-laser-induced material modification is introduced. And then, three different fabrication technologies, i.e., femtosecond laser phase mask technology, femtosecond laser holographic interferometry, and femtosecond laser direct writing technology, are discussed. Finally, the advances in high-temperature sensing applications and vector bending sensing applications of various femtosecond-laser-inscribed FBGs are summarized. Such femtosecond-laser-inscribed FBGs are promising in many industrial areas, such as aerospace vehicles, nuclear plants, oil and gas explorations, and advanced robotics in harsh environments.

光纤布拉格光栅（FBG）由于其紧凑的尺寸，高的灵敏度和易于复用的特性而成为使用最广泛的光纤传感器。通过使用紫外线（UV）激光相位掩膜方法制造的常规FBG需要对光纤进行敏化，因此无法在高温下使用。近年来，由于飞秒激光器在创建具有复杂光谱的FBG阵列或特殊FBG方面具有出色的灵活性，因此使用飞秒激光器制造FBG引起了广泛的关注。飞秒激光还可用于在几乎所有类型的光纤上雕刻各种FBG，甚至是没有任何光敏性的光纤。这种飞秒激光诱导的FBG具有出色的热稳定性，适用于恶劣环境下的传感。在这篇评论中，我们介绍了飞秒激光刻写的FBG的制造技术和传感应用的历史发展和最新进展。首先，介绍了飞秒激光诱导材料改性的机理。然后，讨论了三种不同的制造技术，即飞秒激光相位掩膜技术，飞秒激光全息干涉技术和飞秒激光直接写入技术。最后，总结了各种飞秒激光刻写的FBG在高温传感应用和矢量弯曲传感应用中的进展。这种飞秒激光刻写的FBG在许多工业领域中很有希望，例如航天飞机，核电站，石油和天然气勘探以及恶劣环境中的先进机器人技术。