Advances in distributed vibration sensing for optical communication fiber state visualization

This paper describes our recently proposed novel distributed vibration sensing (DVS) measurement technologies for visualizing the state of optical fiber in communication cables. Conventional fault location of optical fiber cable involves the measurement of just optical loss. However, in recent years, attempts have been made to visualize optical fiber attributes that cannot be observed with conventional technology; a key technique is measuring the distribution of dynamic strain caused by vibration. Accurately capturing the vibration makes it possible to measure the state of various fibers that cannot be realized with conventional loss measurements. In measuring vibration, it is necessary to measure not only the power of the light but also several physical parameters such as the vibrational frequency, which is the time variation of the waveform of scattered light, and the phase of the light itself. In addition, it is also necessary to consider the conventional specifications of optical loss measurement techniques, such as distance resolution and measurement distance, which have been considered in the past. In this paper, we introduce several DVS technologies and show their applicability to various state detection schemes for communication fibers.