Publication detail

Phi-OTDR signal amplification

MÜNSTER, P. VOJTĚCH, J. SYSEL, P. ŠIFTA, R. NOVOTNÝ, V. HORVÁTH, T. FILKA, M. ŠÍMA, S.

Original Title

Phi-OTDR signal amplification

Type

conference paper

Language

English

Original Abstract

Phase-sensitive optical time-domain reflectometry seems to be the most appropriate solution for acoustic vibration along standard optical fiber detection. In general the sensing system measures phase changes of the received Rayleigh back-scattered signal in the fiber. Since the back-scattered signal intensity is decreased about tens of decibels in comparison to the forward propagating pulse power level, the received signal power level is very low. That is why the main limiting parameter of the system is the power level of the back-scattered signal, which limits maximum achievable distance. For long reach sensing it is necessary to create high power optical pulses with short time-duration. Direct pulse amplification by erbium doped fiber amplifier (EDFA) is an issue because of the pulses low repetition rate. We have designed and verified a simple method using a holding beam for amplifying of pulses with low repetition rate by standard telecommunication EDFA booster instead of deployment of an expensive optical shutter. A second CW laser with a different wavelength for EDFA stabilization is used in our setup. Because a pulse losses its energy during propagation in the fiber and with longer distances by 1st order Raman amplifier (RA). In telecommunications this amplifier is used to compensate for fiber losses. The second setup uses remote amplification by remotely pumped erbium doped fiber (EDF) placed after a few tens of kilometers of sensing fiber. A pump laser is placed in the transmitter part of the system from where EDF is pumped. In this paper, we present an overview of few techniques for Phi-ODTR signals amplification and their verification by measurement.

Keywords

optical sensors, phi-ODTR, amplification, Raman, Rayleigh, remote pumping

Authors

MÜNSTER, P.; VOJTĚCH, J.; SYSEL, P.; ŠIFTA, R.; NOVOTNÝ, V.; HORVÁTH, T.; FILKA, M.; ŠÍMA, S.

RIV year

2015

Released

5. 5. 2015

Publisher

SPIE

ISBN

9781628416275

Book

Proc. SPIE 9506, Optical Sensors 2015

Edition number

9506

ISBN

NEUVEDENO

Pages from

1

Pages to

9

Pages count

9

BibTex

@inproceedings{BUT114501,
  author="Petr {Münster} and Josef {Vojtěch} and Petr {Sysel} and Radim {Šifta} and Vít {Novotný} and Tomáš {Horváth} and Miloslav {Filka} and Stanislav {Šíma}",
  title="Phi-OTDR signal amplification",
  booktitle="Proc. SPIE 9506, Optical Sensors 2015",
  year="2015",
  number="9506",
  pages="1--9",
  publisher="SPIE",
  doi="10.1117/12.2179026",
  isbn="9781628416275"
}