Recent Advancements in Optical Frequency-Domain Reflectometry: A Review

Optical frequency-domain reflectometry (OFDR) based on Rayleigh scattering has been widely used for distributed sensing applications for either static or dynamic parameter measurements, such as temperature, strain, and vibration due to its unique capability. In this review article, we report the recent advancements in OFDR-based distributed sensing techniques. First, the sensing principles and signal processing methods of the OFDR system are introduced. Various nonlinear compensation methods are also reviewed and compared to show their advantages and disadvantages. Then, key technologies that are aimed to improve the sensing range, spatial resolution, strain measurement range, and frequency response range are surveyed in detail. Finally, practical applications of the OFDR-based distributed sensing system are introduced, including the measurement of humidity, refractive index, magnetic field, flow rate, gas sensing, radiation sensing, shape sensing, biomedical fields, and so on.