The digital coherent detection method is employed into the φ-OTDR. The heterodyne detection
offers very high optical gain while the digital signal processing serves as an effective tool …

This book describes the latest development in optical fiber devices, and their applications to
sensor technology. Optical fiber sensors, an important application of the optical fiber, have …

The characteristics of interference fading in a phase sensitive optical time domain reflectometer
(φ-OTDR) system with a three optical frequency source are described in this paper. It is …

A laser phase and frequency noise measurement method by an unbalanced Michelson
interferometer composed of a 3 × 3 optical fiber coupler is proposed. The relations and …

A high spatial resolution phase-sensitive optical time domain reflectometer ( ϕ -OTDR) with
an optical frequency-swept pulse (FSP) is proposed, and the experimental results are …

Distributed fiber acoustic sensing (DAS) technology can continuously spatially detect disturbances
along the sensing fiber over long distance in real time. It has many unique advantages…

A phase-sensitive optical time-domain reflectometry ( Φ -OTDR) with a temporally sequenced
multi-frequency (TSMF) source is proposed. This technique can improve the system …

Distributed acoustic sensing (DAS) technology based on Rayleigh backscattering is experiencing
a rapid development and leading itself into wider applications because of the unique …

In this letter, a distributed optical fiber hydrophone (DOFH) based on Φ-OTDR is demonstrated
and tested in the field. The specially designed sensitized optical cable with sensitivity up …

A simple and low-cost 1550 nm semiconductor laser with subkilohertz intrinsic linewidth is
experimentally demonstrated. A commercial distributed feedback diode laser is self-injection …