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Miguel Gonzalezherraez - One of the best experts on this subject based on the ideXlab platform.

  • distributed phase birefringence measurements based on polarization correlation in phase sensitive Optical Time domain reflectometers
    Optics Express, 2015
    Co-Authors: Marcelo A Soto, Xin Lu, Miguel Gonzalezherraez, Hugo F Martins, Luc Thevenaz
    Abstract:

    In this paper a technique to measure the distributed birefringence profile along Optical fibers is proposed and experimentally validated. The method is based on the spectral correlation between two sets of orthogonally-polarized measurements acquired using a phase-sensitive Optical Time-domain reflectometer (ϕOTDR). The correlation between the two measured spectra gives a resonance (correlation) peak at a frequency detuning that is proportional to the local refractive index difference between the two orthogonal polarization axes of the fiber. In this way the method enables local phase birefringence measurements at any position along Optical fibers, so that any longitudinal fluctuation can be precisely evaluated with metric spatial resolution. The method has been experimentally validated by measuring fibers with low and high birefringence, such as standard single-mode fibers as well as conventional polarization-maintaining fibers. The technique has potential applications in the characterization of Optical fibers for telecommunications as well as in distributed Optical fiber sensing.

  • non local effects in dual probe sideband brillouin Optical Time domain analysis
    Optics Express, 2015
    Co-Authors: Alejandro Dominguezlopez, Xabier Angulovinuesa, Sonia Martinlopez, Alexia Lopezgil, Miguel Gonzalezherraez
    Abstract:

    According to recent models, non-local effects in dual-probe-sideband Brillouin Optical Time Domain Analysis (BOTDA) systems should be essentially negligible whenever the probe power is below the Stimulated Brillouin Scattering (SBS) threshold. This paper shows that actually there appear non-local effects in this type of systems before the SBS threshold. To explain these effects it is necessary to take into account a full spectral description of the SBS process. The pump pulse experiences a frequency-dependent spectral deformation that affects the readout process differently in the gain and loss configurations. This paper provides a simple analytical model of this phenomenon, which is validated against compelling experimental data, showing good agreement. The main conclusion of our study is that the measurements in gain configuration are more robust to this non-local effect than the loss configuration. Experimental and theoretical results show that, for a total probe wave power of ~1 mW (500 μW on each sideband), there is an up-shifting of ~1 MHz in the Brillouin Frequency Shift (BFS) retrieved from the Brillouin Loss Spectrum, whereas the BFS extracted from the measured Brillouin Gain Spectrum is up-shifted only ~0.6 MHz. These results are of particular interest for manufacturers of long-range BOTDA systems.

  • raman assisted brillouin Optical Time domain analysis with sub meter resolution over 100 km
    Optics Express, 2012
    Co-Authors: Xabier Angulovinuesa, Pedro Corredera, Sonia Martinlopez, Miguel Gonzalezherraez
    Abstract:

    Sub-meter resolution in long-distance Brillouin Optical Time Domain Analysis (BOTDA) cannot be trivially achieved due to several issues including: resolution-uncertainty trade-offs, self-phase modulation, fiber attenuation, depletion, etc. In this paper we show that combining Raman assistance, differential pulse-width pair (DPP) measurements and a novel numerical de-noising procedure, we could obtain sub-meter resolution Brillouin Optical Time-domain analysis over a range of 100 km. We successfully demonstrate the detection of a 0.5 meter hot-spot in the position of worst contrast along the fiber.

  • brillouin Optical Time domain analysis assisted by second order raman amplification
    Optics Express, 2010
    Co-Authors: Sonia Martinlopez, Luc Thevenaz, Pedro Corredera, M Alconcamas, Felix Rodriguez, Juan Diego Aniacastanon, Miguel Gonzalezherraez
    Abstract:

    We propose and experimentally demonstrate a new method to extend the range of Brillouin Optical Time domain analysis (BOTDA) systems. It exploits the virtual transparency created by second-order Raman pumping in Optical fibers. The idea is theoretically analyzed and experimentally demonstrated in a 50 km fiber. By working close to transparency, we also show that the measurement length of the BOTDA can be increased up to 100 km with 2 meter resolution. We envisage extensions of this technique to measurement lengths well beyond this value, as long as the issue of relative intensity noise (RIN) of the primary Raman pump can be avoided.

Luc Thevenaz - One of the best experts on this subject based on the ideXlab platform.

  • distributed phase birefringence measurements based on polarization correlation in phase sensitive Optical Time domain reflectometers
    Optics Express, 2015
    Co-Authors: Marcelo A Soto, Xin Lu, Miguel Gonzalezherraez, Hugo F Martins, Luc Thevenaz
    Abstract:

    In this paper a technique to measure the distributed birefringence profile along Optical fibers is proposed and experimentally validated. The method is based on the spectral correlation between two sets of orthogonally-polarized measurements acquired using a phase-sensitive Optical Time-domain reflectometer (ϕOTDR). The correlation between the two measured spectra gives a resonance (correlation) peak at a frequency detuning that is proportional to the local refractive index difference between the two orthogonal polarization axes of the fiber. In this way the method enables local phase birefringence measurements at any position along Optical fibers, so that any longitudinal fluctuation can be precisely evaluated with metric spatial resolution. The method has been experimentally validated by measuring fibers with low and high birefringence, such as standard single-mode fibers as well as conventional polarization-maintaining fibers. The technique has potential applications in the characterization of Optical fibers for telecommunications as well as in distributed Optical fiber sensing.

  • extending the sensing range of brillouin Optical Time domain analysis up to 325 km combining four Optical repeaters
    Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series, 2014
    Co-Authors: Flavien Gyger, Etienne Rochat, Sanghoon Chin, Marc Nikles, Luc Thevenaz
    Abstract:

    A novel scheme is proposed to extend the sensing range of Brillouin Optical Time-domain analyzers (BOTDA). Specially-designed erbium doped fiber amplifier (EDFA) repeaters are located every 65km fiber along the sensing cable to achieve a total sensing length of 325km, corresponding to a 650km loop. At the end of the sensing fibre, we experimentally demonstrated a measurement repeatability of 2°C (2Ϛ ) using a three meters spatial resolution.

  • long range brillouin Optical Time domain analysis sensor employing pulse coding techniques
    Measurement Science and Technology, 2010
    Co-Authors: G Bolognini, Marcelo A Soto, Fabrizio Di Pasquale, Luc Thevenaz
    Abstract:

    In this paper we describe and implement a long-range Brillouin Optical Time-domain analysis (BOTDA) sensor, for both temperature and strain measurements, using Optical pulse coding techniques. A theoretical analysis of Simplex coding applied to BOTDA systems is presented and experimentally demonstrated for both Brillouin loss and Brillouin gain configurations. With the proposed technique, ~7.1 dB and ~10.3 dB of signal-to-noise ratio improvements are demonstrated in BOTDA measurements using 127-bit and 511-bit Simplex codes, respectively. This feature allows us to extend the dynamic range of the measurements, overcoming the limitations to the maximum usable Optical power imposed by pump depletion and modulation instability; thus, the sensing range can be extended by several tens of kilometers while keeping meter-scale spatial resolution. Experimental results show the capabilities of Optical pulse coding techniques to achieve 1 m spatial resolution over 50 km of standard single-mode fiber enabling temperature and strain resolutions equal to 2.2 °C and 44 µe, respectively.

  • brillouin Optical Time domain analysis assisted by second order raman amplification
    Optics Express, 2010
    Co-Authors: Sonia Martinlopez, Luc Thevenaz, Pedro Corredera, M Alconcamas, Felix Rodriguez, Juan Diego Aniacastanon, Miguel Gonzalezherraez
    Abstract:

    We propose and experimentally demonstrate a new method to extend the range of Brillouin Optical Time domain analysis (BOTDA) systems. It exploits the virtual transparency created by second-order Raman pumping in Optical fibers. The idea is theoretically analyzed and experimentally demonstrated in a 50 km fiber. By working close to transparency, we also show that the measurement length of the BOTDA can be increased up to 100 km with 2 meter resolution. We envisage extensions of this technique to measurement lengths well beyond this value, as long as the issue of relative intensity noise (RIN) of the primary Raman pump can be avoided.

  • A high-performance Optical Time-domain brillouin distributed fiber sensor
    IEEE Sensors Journal, 2008
    Co-Authors: Silvia Diaz, Stella Foaleng Mafang, Manuel Lopez-amo, Luc Thevenaz
    Abstract:

    A novel configuration for a Brillouin distributed fiber sensor based on Brillouin Optical Time-domain analysis is proposed. This configuration eliminates many intensity noise issues found in previous schemes. Resolution of 7 m all over a 47 km single-mode fiber was achieved and resolution down to 30 cm in a few kilo- meter fiber. Noise reduction makes possible measurements with a 16 Times averaging

Alayn Loayssa - One of the best experts on this subject based on the ideXlab platform.

  • Brillouin Optical Time-domain analysis sensor assisted by Brillouin distributed amplification of pump pulses.
    Optics Express, 2015
    Co-Authors: Javier Urricelqui, Mikel Sagues, Alayn Loayssa
    Abstract:

    We demonstrate the extension of the measurement range of Brillouin Optical Time-domain analysis (BOTDA) sensors using a distributed Brillouin amplifier (DBA). The technique is based on injecting a DBA pump wave in the fiber to generate an additional Brillouin interaction that amplifies the BOTDA pump pulses and compensates Optical fiber attenuation. This amplification does not introduce any significant noise to the BOTDA’s probe wave due to the inherent directionality of the Brillouin gain. Additionally, we deploy a differential pulse-width pair measurement method to avoid measurement errors due to the interplay between the self-phase modulation effect and the changes in the temporal shape of the pulses induced by the transient behavior of Brillouin gain. Experimental proof-of-concept results in a 50-km fiber link demonstrate full compensation of the fiber’s attenuation with no penalty on the signal-to-noise ratio of the detected signal.

  • Phasorial differential pulse-width pair technique for long-range Brillouin Optical Time-domain analysis sensors
    Optics Express, 2014
    Co-Authors: Javier Urricelqui, Mikel Sagues, Alayn Loayssa
    Abstract:

    We introduce a novel phasorial differential pulse-width pair (PDPP) method for Brillouin Optical Time-domain analysis (BOTDA) sensors that combines spatial resolution enhancement with increased tolerance to non-local effects. It is based on the subtraction of the complex Time-domain traces supplied by a sensor configuration that uses a phase-modulated probe wave and RF demodulation. The fundamentals of the technique are first described theoretically and using numerical simulation of the propagating waves. Then, proof-of-concept experiments demonstrate the measurement of the Brillouin frequency shift distribution over 50-km. The system is shown to withstand large variations of the pump power generated by its interaction with a powerful probe wave along the fiber; hence, highlighting the potential of the PDPP technique to increase the detected signal-to-noise ratio in long-range BOTDA. Moreover, the PDPP is also shown to increase the measurement contrast by allowing the use of relatively long duration pulses while retaining 1-m spatial resolution.

Henry F Taylor - One of the best experts on this subject based on the ideXlab platform.

Juichi Noda - One of the best experts on this subject based on the ideXlab platform.