Distributed Fiber-Optic Probing using the Optical Reflectometry Method

The paper is devoted to the analysis of the application of the Rayleigh reflectometry method for fiber-optic sensing. Initially, it was used in optical telecommunications to measure the attenuation profile uniformity of optical fibers. The method involves the insertion of the short probing pulse into the fiber under test. The work analyzes the evolution of pulse propagation along the probed fiber, which lose some of the power in their path due to various attenuation mechanisms, including Rayleigh scattering. Moreover, this work demonstrates a functional connection between the probing pulse energy and the backscatter power signal. The backscattering power is proved to be a purely exponential function of the position along the fiber. The spatial resolution of the reflectometer is determined by the convolution of the probing pulse waveform, the impulse response of the capture and the impulse response of the fiber at the two-way transition from the starting end to the controlled point and backwards. Methods for solving the problem of low levels of Rayleigh scattering signal are proposed. The study analyses the development trends and the scope of application of Rayleigh reflectometry for distributed probing. At the same time, special emphasis is placed on the use in high-speed telecommunication systems. The results of experimental studies indicating the functional capabilities of the fiber-optic sensing method are presented. The method is very effective at the stages of construction and technical operation of fiber-optic communication lines.