Open AccessDirect detection based φOTDR using the Kramers-Kronig receiver
Author(s) -
Xin Lu,
Katerina Krebber
Publication year - 2020
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.405723
Subject(s) - optics , optical time domain reflectometer , interferometry , demodulation , reflectometry , physics , kramers–kronig relations , signal processing , phase modulation , signal (programming language) , phase (matter) , time domain , refractive index , optical fiber , fiber optic sensor , computer science , telecommunications , phase noise , channel (broadcasting) , fiber optic splitter , radar , quantum mechanics , computer vision , programming language
A Kramers-Kronig (KK) receiver is applied to a phase-sensitive optical time domain reflectometry based on direct detection. An imbalanced Mach-Zehnder interferometer with a 2×2 coupler is used in sensing system to encode the phase information into optical intensity. The directly obtained signal is treated as the in-phase component, and the KK receiver provides the quadrature component by Hilbert transform of the obtained signal, so that the optical phase can be retrieved by IQ demodulation. The working principle is well explained, and the obtained phase variance is theoretically analyzed. The experiment demonstrates the functionality of the sensor and validates the theoretical analysis.