5,000 points/s high-speed random accessibility for dynamic strain measurement at arbitrary multiple points along a fiber by Brillouin optical correlation domain analysis

Chunyu Zhang, Masato Kishi and Kazuo Hotate

Department of Electrical Engineering and Information Systems, The University of Tokyo, Bunkyo, Tokyo 113-8656, Japan 

2015 Appl. Phys. Express 8 042501 doi:10.7567/APEX.8.042501

ABSTRACT

We demonstrate dynamic strain measurement at arbitrary multiple points along a fiber simultaneously using random accessibility of a Brillouin optical correlation domain analysis system with a 5,000 points/s sampling rate. A voltage-controlled oscillator is introduced for faster sweeping of the probe wave frequency to obtain the Brillouin gain spectrum. A higher-speed lock-in amplifier is also used for data detection. Several patterns of dynamic strain applied at five points selected arbitrarily along the fiber are measured simultaneously at a 5,000 points/s sampling rate with random accessibility. This is the highest speed of random accessibility reported so far in Brillouin-based distributed fiber sensors.