Abstract

We propose a simple fiber optic BOCDA (Brillouin Optical Correlation Domain Analysis) sensor using phase modulation of pump and probe lights without a delay optical fiber line. In order to clearly select the measurement position in the sensing optical fiber with the BOCDA sensor, it is just necessary to set the time difference of phase modulation between pump and probe with PRBS (Pseudo Random Bit Sequence) code. A sensor system was constructed using two phase modulators and a PPG(pulse pattern generator) having 2 channel outputs with 5 GHz. This PPG made two codes having the time difference to modulate the pump and probe lights. In the experiment, this sensor could determine Brillouin frequencies through all position of the sensing fiber very clearly. It could also be seen that the sensor system achieves a spatial resolution of 2 cm, the Brillouin frequency resolution is 0.5 MHz.

© 2018 The Author(s)