Cover story: Liu HH, Hu DJJ, Sun QZ, Wei L, Li KW et al. Specialty optical fibers for advanced sensing applications. Opto-Electron Sci 2, 220025 (2023).

Optical fiber technology has changed the world in enabling extraordinary growth in world-wide communications and sensing. Since the optical fiber communication was first proposed by Charles Kao in 1966, fiber loss has reduced from 1000 dB/km to today’s <0.2 dB/km. Optical fiber sensors offer favorable advantages such as immunity to electromagnetic interference, lightweight, small size, high sensitivity, large bandwidth, reliable and robust performance, ability to withstand harsh environment, and ease in implementing multiplexed or distributed sensors. In 1996, Philip Russell’s research group fabricated the first photonic crystal fiber which made the design and fabrication of optical fiber three-dimensional and more sophisticated fiber-based devices were being developed. Specialty optical fibers differ greatly from conventional communication optical fibers in doping elements, working wavelengths, structure, and optical properties. Notably, the research on specialty optical fibers is playing a critical role in enabling and proliferating optical fiber sensing applications. Compared with traditional optical fiber sensors, sensor performance such as sensitivity, accuracy and sensing range can be significantly improved by utilizing specialty optical fiber-based sensors, making them suitable for a wide range of sensing applications. Up to date, specialty optical fiber sensors have been extensively utilized and investigated for various applications, including civil engineering, environmental monitoring, agricultural engineering, biomedical engineering, and more.