Advances in Distributed Optical Fiber Sensors Based on Optical Frequency-Domain Reflectometry: A Review

Optical frequency-domain reflectometry (OFDR) offers a unique combination of ultrahigh spatial resolution and sensitivity, which makes OFDR one of the most rapidly developing fields of distributed optical fiber sensing (DOFS), especially in 3-D shape sensing, acoustic sensing, dynamic strain sensing, and refractive index (RI) sensing besides temperature and static strain. In this review, we covered key technological developments and insights of OFDR in recent years, which includes nonlinear tuning correction, fast spectrum analysis, Rayleigh backscattering spectra demodulation, Rayleigh scattering enhancement fiber, phase-based demodulation, high-temperature sensing, dynamic strain sensing, acoustic sensing, 3-D shape sensing, RI sensing, biochemical sensing, polarimetric OFDR sensing, and photonic integrated circuit-based OFDR. Finally, we presented the challenges and prospects of DOFS based on OFDR.