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Journal of Sensors
Volume 2018 (2018), Article ID 4848254, 11 pages
Research Article

Distributed Intrusion Sensor Using DFB Laser with Optical Feedback and Saturable Absorber

Department of Information and Telecommunication Engineering, Incheon National University, Incheon 22012, Republic of Korea

Correspondence should be addressed to Kyoo Nam Choi

Received 18 September 2017; Revised 14 December 2017; Accepted 26 December 2017; Published 8 February 2018

Academic Editor: Stefano Stassi

Copyright © 2018 Kyoo Nam Choi. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Characteristics of a distributed intrusion sensor using a coherent DFB laser diode with an external optical feedback and saturable absorber were experimentally investigated. The stimulus at a location of 2 km using a PZT transducer placed the location of a simulated intruder in Φ-OTDR trace after averaging 32 times. Field trials demonstrated the detection of a vehicle and a pedestrian crossing above the sensing line and a loop in a burial depth of 50 cm. This distributed intrusion sensor using a coherent DFB laser diode as the light source had the advantages of a simple structure and intruder detection capability at the underground burial location.