title: High-resolution DPP-BOTDA over 50 km LEAF using return-to-zero coded pulses.
abstract: Coded optical probe pulses in return-to-zero/non-return-to-zero (RZ/NRZ) formats are used for long-range distance sensing based on a differential pulse-width pair Brillouin optical time-domain analysis (DPP-BOTDA) in order to enhance the spatial resolution and measurement accuracy. It is found that using the RZ format maintains the Brillouin spectral shape, enhances the sensing range and leads to a higher signal-to-noise ratio compared to a single-pulse Brillouin optical time-domain analysis. With 512 bit RZ-coded pulse pairs of 60/55 ns for the DPP-BOTDA, a spatial resolution of approximately 0.5 m and a strain resolution of 12 microepsilon (which is equivalent to a 0.7 MHz Brillouin frequency shift) have been achieved over a 50 km large effective area fiber.
authors.affiliation: Fiber Optics Group, Department of Physics, University of Ottawa, Ottawa, Ontario K1N6N5, Canada.
authors.forename: Hao
authors.initials: H
authors.lastname: Liang
authors.forename: Wenhai
authors.initials: W
authors.lastname: Li
authors.forename: Nicolas
authors.initials: N
authors.lastname: Linze
authors.forename: Liang
authors.initials: L
authors.lastname: Chen
authors.forename: Xiaoyi
authors.initials: X
authors.lastname: Bao