Abstract

Brillouin optical correlation-domain analysis (B-OCDA) allows for distributed measurements of strain and temperature with sub-cm resolution. Time-multiplexing techniques have previously extended B-OCDA to the monitoring of many km of fiber and two million resolution points. Thus far, however, the number of scans of correlation peaks positions, necessary to cover the fiber under test, was restricted to the order of 100 or more. In this work we report a B-OCDA protocol that is able to address an entire fiber using only 11 pairs of position scans per choice of frequency. The measurements protocol relies on a merger between B-OCDA principles and double-pulse-pair analysis, previously incorporated in time-domain Brillouin sensors. Phase coding of the pump and signal waves with a repeating, short and high-rate code stimulates Brillouin interactions in a large number of narrow correlation peaks, with substantial temporal overlap. Unambiguous measurements are achieved by repeating each experiment twice, using a pair of pump pulses of different durations, and subtracting the two output traces. The principle is demonstrated in the analysis of a 43 m-long fiber with 2.7 cm resolution. Several local hot-spots are properly identified in the measurements. The experimental uncertainty in the measurement of the local Brillouin frequency shift is estimated as ± 1.9 MHz. The proposed method requires broader detection bandwidth and a larger number of averages than those of previous time-gated B-OCDA setups. Hence the overall number of measurements is similar to that of previous setups.

© 2016 Optical Society of America

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References

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  1. R. W. Boyd, Nonlinear Optics, 3rd ed. (Academic, 2008).
  2. T. Horiguchi, T. Kurashima, and M. Tateda, “A technique to measure distributed strain in optical fibers,” IEEE Photonics Technol. Lett. 2(5), 352–354 (1990).
    [Crossref]
  3. M. Niklès, L. Thévenaz, and P. A. Robert, “Simple distributed fiber sensor based on Brillouin gain spectrum analysis,” Opt. Lett. 21(10), 758–760 (1996).
    [Crossref] [PubMed]
  4. F. Gyger, E. Rochat, S. Chin, M. Niklès, and L. Thévenaz, “Extending the sensing range of Brillouin optical time-domain analysis up to 325 km combining four optical repeaters,” Proc. SPIE 9157, 91576Q (2014).
    [Crossref]
  5. I. Sovran, A. Motil, and M. Tur, “Frequency-scanning BOTDA with ultimately fast acquisition speed,” IEEE Photonics Technol. Lett. 27(13), 1426–1429 (2015).
    [Crossref]
  6. A. Motil, A. Bergman, and M. Tur, “[INVITED] State of the art of Brillouin fiber-optic distributed sensing,” Opt. Laser Technol. 78, 81–103 (2016).
    [Crossref]
  7. A. Fellay, L. Thévenaz, M. Facchini, M. Nikles, and P. A. Robert, “Distributed sensing using stimulated Brillouin scattering: towards ultimate resolution,” in Proc. of 12th Optical Fiber Sensors Conference (Optical Society of America, 1997), paper OWD3.
    [Crossref]
  8. S. M. Foaleng, M. Tur, J. C. Beugnot, and L. Thevenaz, “High spatial and spectral resolution long-range sensing using Brillouin echoes,” J. Lightwave Technol. 28(20), 2993–3003 (2010).
    [Crossref]
  9. Y. Dong, H. Zhang, L. Chen, and X. Bao, “2 cm spatial-resolution and 2 km range Brillouin optical fiber sensor using a transient differential pulse pair,” Appl. Opt. 51(9), 1229–1235 (2012).
    [Crossref] [PubMed]
  10. K. Hotate and T. Hasegawa, “Measurement of Brillouin gain spectrum distribution along an optical fiber using a correlation-based technique -proposal, experiment and simulation,” IEICE T. Electorn E83-C(3), 405–412 (2000).
  11. Y. Antman, N. Primerov, J. Sancho, L. Thévenaz, and A. Zadok, “Localized and stationary dynamic gratings via stimulated Brillouin scattering with phase modulated pumps,” Opt. Express 20(7), 7807–7821 (2012).
    [Crossref] [PubMed]
  12. K. Y. Song, Z. He, and K. Hotate, “Distributed strain measurement with millimeter-order spatial resolution based on Brillouin optical correlation domain analysis,” Opt. Lett. 31(17), 2526–2528 (2006).
    [Crossref] [PubMed]
  13. K. Hotate, H. Arai, and K. Y. Song, “Range-enlargement of simplified Brillouin optical correlation domain analysis based on a temporal gating scheme,” SICE J. Control Meas. Sys. Integration 1(4), 271–274 (2008).
    [Crossref]
  14. D. Elooz, Y. Antman, N. Levanon, and A. Zadok, “High-resolution long-reach distributed Brillouin sensing based on combined time-domain and correlation-domain analysis,” Opt. Express 22(6), 6453–6463 (2014).
    [Crossref] [PubMed]
  15. Y. London, Y. Antman, R. Cohen, N. Kimelfeld, N. Levanon, and A. Zadok, “High-resolution long-range distributed Brillouin analysis using dual-layer phase and amplitude coding,” Opt. Express 22(22), 27144–27158 (2014).
    [Crossref] [PubMed]
  16. Y. H. Kim, K. Lee, and K. Y. Song, “Brillouin optical correlation domain analysis with more than 1 million effective sensing points based on differential measurement,” Opt. Express 23(26), 33241–33248 (2015).
    [Crossref] [PubMed]
  17. Y. London, Y. Antman, E. Preter, N. Levanon, and A. Zadok, “Brillouin optical correlation domain analysis addressing 440,000 resolution points,” J. Lightwave Technol.34, in press (2016).
  18. A. Denisov, M. A. Soto, and L. Thevenaz, “Going beyond 1000000 resolved points in a Brillouin distributed fiber sensor: theoretical analysis and experimental demonstration,” Light Sci. Appl. 5(5), e16074 (2016).
    [Crossref]
  19. S. W. Golomb, “Two-valued sequences with perfect periodic autocorrelation,” IEEE Trans. Aero. Electron. Sys. 28(2), 383–386 (1992).
    [Crossref]
  20. Y. Antman, N. Levanon, and A. Zadok, “Low-noise delays from dynamic Brillouin gratings based on perfect Golomb coding of pump waves,” Opt. Lett. 37(24), 5259–5261 (2012).
    [Crossref] [PubMed]
  21. A. Zadok, Y. Antman, N. Primerov, A. Denisov, J. Sancho, and L. Thevenaz, “Random-access distributed fiber sensing,” Laser Photonics Rev. 6(5), L1–L5 (2012).
    [Crossref]
  22. A. Zadok, E. Zilka, A. Eyal, L. Thévenaz, and M. Tur, “Vector analysis of stimulated Brillouin scattering amplification in standard single-mode fibers,” Opt. Express 16(26), 21692–21707 (2008).
    [Crossref] [PubMed]
  23. M. A. Soto and L. Thévenaz, “Modeling and evaluating the performance of Brillouin distributed optical fiber sensors,” Opt. Express 21(25), 31347–31366 (2013).
    [Crossref] [PubMed]
  24. J. Urricelqui, F. Lopez-Fernandino, M. Sagues, and A. Loayssa, “Polarization diversity scheme for BOTDA sensors based on a double orthogonal pump interaction,” J. Lightwave Technol. 33(12), 2633–2638 (2015).
    [Crossref]
  25. A. Lopez-Gil, A. Dominguez-Lopez, S. Martin-Lopez, and M. Gonzalez-Herraez, “Simple Method for the Elimination of Polarization Noise in BOTDA Using Balanced Detection and Orthogonal Probe Sidebands,” J. Lightwave Technol. 33(12), 2605–2610 (2015).
    [Crossref]

2016 (2)

A. Motil, A. Bergman, and M. Tur, “[INVITED] State of the art of Brillouin fiber-optic distributed sensing,” Opt. Laser Technol. 78, 81–103 (2016).
[Crossref]

A. Denisov, M. A. Soto, and L. Thevenaz, “Going beyond 1000000 resolved points in a Brillouin distributed fiber sensor: theoretical analysis and experimental demonstration,” Light Sci. Appl. 5(5), e16074 (2016).
[Crossref]

2015 (4)

2014 (3)

2013 (1)

2012 (4)

2010 (1)

2008 (2)

K. Hotate, H. Arai, and K. Y. Song, “Range-enlargement of simplified Brillouin optical correlation domain analysis based on a temporal gating scheme,” SICE J. Control Meas. Sys. Integration 1(4), 271–274 (2008).
[Crossref]

A. Zadok, E. Zilka, A. Eyal, L. Thévenaz, and M. Tur, “Vector analysis of stimulated Brillouin scattering amplification in standard single-mode fibers,” Opt. Express 16(26), 21692–21707 (2008).
[Crossref] [PubMed]

2006 (1)

2000 (1)

K. Hotate and T. Hasegawa, “Measurement of Brillouin gain spectrum distribution along an optical fiber using a correlation-based technique -proposal, experiment and simulation,” IEICE T. Electorn E83-C(3), 405–412 (2000).

1996 (1)

1992 (1)

S. W. Golomb, “Two-valued sequences with perfect periodic autocorrelation,” IEEE Trans. Aero. Electron. Sys. 28(2), 383–386 (1992).
[Crossref]

1990 (1)

T. Horiguchi, T. Kurashima, and M. Tateda, “A technique to measure distributed strain in optical fibers,” IEEE Photonics Technol. Lett. 2(5), 352–354 (1990).
[Crossref]

Antman, Y.

Arai, H.

K. Hotate, H. Arai, and K. Y. Song, “Range-enlargement of simplified Brillouin optical correlation domain analysis based on a temporal gating scheme,” SICE J. Control Meas. Sys. Integration 1(4), 271–274 (2008).
[Crossref]

Bao, X.

Bergman, A.

A. Motil, A. Bergman, and M. Tur, “[INVITED] State of the art of Brillouin fiber-optic distributed sensing,” Opt. Laser Technol. 78, 81–103 (2016).
[Crossref]

Beugnot, J. C.

Chen, L.

Chin, S.

F. Gyger, E. Rochat, S. Chin, M. Niklès, and L. Thévenaz, “Extending the sensing range of Brillouin optical time-domain analysis up to 325 km combining four optical repeaters,” Proc. SPIE 9157, 91576Q (2014).
[Crossref]

Cohen, R.

Denisov, A.

A. Denisov, M. A. Soto, and L. Thevenaz, “Going beyond 1000000 resolved points in a Brillouin distributed fiber sensor: theoretical analysis and experimental demonstration,” Light Sci. Appl. 5(5), e16074 (2016).
[Crossref]

A. Zadok, Y. Antman, N. Primerov, A. Denisov, J. Sancho, and L. Thevenaz, “Random-access distributed fiber sensing,” Laser Photonics Rev. 6(5), L1–L5 (2012).
[Crossref]

Dominguez-Lopez, A.

Dong, Y.

Elooz, D.

Eyal, A.

Foaleng, S. M.

Golomb, S. W.

S. W. Golomb, “Two-valued sequences with perfect periodic autocorrelation,” IEEE Trans. Aero. Electron. Sys. 28(2), 383–386 (1992).
[Crossref]

Gonzalez-Herraez, M.

Gyger, F.

F. Gyger, E. Rochat, S. Chin, M. Niklès, and L. Thévenaz, “Extending the sensing range of Brillouin optical time-domain analysis up to 325 km combining four optical repeaters,” Proc. SPIE 9157, 91576Q (2014).
[Crossref]

Hasegawa, T.

K. Hotate and T. Hasegawa, “Measurement of Brillouin gain spectrum distribution along an optical fiber using a correlation-based technique -proposal, experiment and simulation,” IEICE T. Electorn E83-C(3), 405–412 (2000).

He, Z.

Horiguchi, T.

T. Horiguchi, T. Kurashima, and M. Tateda, “A technique to measure distributed strain in optical fibers,” IEEE Photonics Technol. Lett. 2(5), 352–354 (1990).
[Crossref]

Hotate, K.

K. Hotate, H. Arai, and K. Y. Song, “Range-enlargement of simplified Brillouin optical correlation domain analysis based on a temporal gating scheme,” SICE J. Control Meas. Sys. Integration 1(4), 271–274 (2008).
[Crossref]

K. Y. Song, Z. He, and K. Hotate, “Distributed strain measurement with millimeter-order spatial resolution based on Brillouin optical correlation domain analysis,” Opt. Lett. 31(17), 2526–2528 (2006).
[Crossref] [PubMed]

K. Hotate and T. Hasegawa, “Measurement of Brillouin gain spectrum distribution along an optical fiber using a correlation-based technique -proposal, experiment and simulation,” IEICE T. Electorn E83-C(3), 405–412 (2000).

Kim, Y. H.

Kimelfeld, N.

Kurashima, T.

T. Horiguchi, T. Kurashima, and M. Tateda, “A technique to measure distributed strain in optical fibers,” IEEE Photonics Technol. Lett. 2(5), 352–354 (1990).
[Crossref]

Lee, K.

Levanon, N.

Loayssa, A.

London, Y.

Y. London, Y. Antman, R. Cohen, N. Kimelfeld, N. Levanon, and A. Zadok, “High-resolution long-range distributed Brillouin analysis using dual-layer phase and amplitude coding,” Opt. Express 22(22), 27144–27158 (2014).
[Crossref] [PubMed]

Y. London, Y. Antman, E. Preter, N. Levanon, and A. Zadok, “Brillouin optical correlation domain analysis addressing 440,000 resolution points,” J. Lightwave Technol.34, in press (2016).

Lopez-Fernandino, F.

Lopez-Gil, A.

Martin-Lopez, S.

Motil, A.

A. Motil, A. Bergman, and M. Tur, “[INVITED] State of the art of Brillouin fiber-optic distributed sensing,” Opt. Laser Technol. 78, 81–103 (2016).
[Crossref]

I. Sovran, A. Motil, and M. Tur, “Frequency-scanning BOTDA with ultimately fast acquisition speed,” IEEE Photonics Technol. Lett. 27(13), 1426–1429 (2015).
[Crossref]

Niklès, M.

F. Gyger, E. Rochat, S. Chin, M. Niklès, and L. Thévenaz, “Extending the sensing range of Brillouin optical time-domain analysis up to 325 km combining four optical repeaters,” Proc. SPIE 9157, 91576Q (2014).
[Crossref]

M. Niklès, L. Thévenaz, and P. A. Robert, “Simple distributed fiber sensor based on Brillouin gain spectrum analysis,” Opt. Lett. 21(10), 758–760 (1996).
[Crossref] [PubMed]

Preter, E.

Y. London, Y. Antman, E. Preter, N. Levanon, and A. Zadok, “Brillouin optical correlation domain analysis addressing 440,000 resolution points,” J. Lightwave Technol.34, in press (2016).

Primerov, N.

A. Zadok, Y. Antman, N. Primerov, A. Denisov, J. Sancho, and L. Thevenaz, “Random-access distributed fiber sensing,” Laser Photonics Rev. 6(5), L1–L5 (2012).
[Crossref]

Y. Antman, N. Primerov, J. Sancho, L. Thévenaz, and A. Zadok, “Localized and stationary dynamic gratings via stimulated Brillouin scattering with phase modulated pumps,” Opt. Express 20(7), 7807–7821 (2012).
[Crossref] [PubMed]

Robert, P. A.

Rochat, E.

F. Gyger, E. Rochat, S. Chin, M. Niklès, and L. Thévenaz, “Extending the sensing range of Brillouin optical time-domain analysis up to 325 km combining four optical repeaters,” Proc. SPIE 9157, 91576Q (2014).
[Crossref]

Sagues, M.

Sancho, J.

Y. Antman, N. Primerov, J. Sancho, L. Thévenaz, and A. Zadok, “Localized and stationary dynamic gratings via stimulated Brillouin scattering with phase modulated pumps,” Opt. Express 20(7), 7807–7821 (2012).
[Crossref] [PubMed]

A. Zadok, Y. Antman, N. Primerov, A. Denisov, J. Sancho, and L. Thevenaz, “Random-access distributed fiber sensing,” Laser Photonics Rev. 6(5), L1–L5 (2012).
[Crossref]

Song, K. Y.

Soto, M. A.

A. Denisov, M. A. Soto, and L. Thevenaz, “Going beyond 1000000 resolved points in a Brillouin distributed fiber sensor: theoretical analysis and experimental demonstration,” Light Sci. Appl. 5(5), e16074 (2016).
[Crossref]

M. A. Soto and L. Thévenaz, “Modeling and evaluating the performance of Brillouin distributed optical fiber sensors,” Opt. Express 21(25), 31347–31366 (2013).
[Crossref] [PubMed]

Sovran, I.

I. Sovran, A. Motil, and M. Tur, “Frequency-scanning BOTDA with ultimately fast acquisition speed,” IEEE Photonics Technol. Lett. 27(13), 1426–1429 (2015).
[Crossref]

Tateda, M.

T. Horiguchi, T. Kurashima, and M. Tateda, “A technique to measure distributed strain in optical fibers,” IEEE Photonics Technol. Lett. 2(5), 352–354 (1990).
[Crossref]

Thevenaz, L.

A. Denisov, M. A. Soto, and L. Thevenaz, “Going beyond 1000000 resolved points in a Brillouin distributed fiber sensor: theoretical analysis and experimental demonstration,” Light Sci. Appl. 5(5), e16074 (2016).
[Crossref]

A. Zadok, Y. Antman, N. Primerov, A. Denisov, J. Sancho, and L. Thevenaz, “Random-access distributed fiber sensing,” Laser Photonics Rev. 6(5), L1–L5 (2012).
[Crossref]

S. M. Foaleng, M. Tur, J. C. Beugnot, and L. Thevenaz, “High spatial and spectral resolution long-range sensing using Brillouin echoes,” J. Lightwave Technol. 28(20), 2993–3003 (2010).
[Crossref]

Thévenaz, L.

Tur, M.

A. Motil, A. Bergman, and M. Tur, “[INVITED] State of the art of Brillouin fiber-optic distributed sensing,” Opt. Laser Technol. 78, 81–103 (2016).
[Crossref]

I. Sovran, A. Motil, and M. Tur, “Frequency-scanning BOTDA with ultimately fast acquisition speed,” IEEE Photonics Technol. Lett. 27(13), 1426–1429 (2015).
[Crossref]

S. M. Foaleng, M. Tur, J. C. Beugnot, and L. Thevenaz, “High spatial and spectral resolution long-range sensing using Brillouin echoes,” J. Lightwave Technol. 28(20), 2993–3003 (2010).
[Crossref]

A. Zadok, E. Zilka, A. Eyal, L. Thévenaz, and M. Tur, “Vector analysis of stimulated Brillouin scattering amplification in standard single-mode fibers,” Opt. Express 16(26), 21692–21707 (2008).
[Crossref] [PubMed]

Urricelqui, J.

Zadok, A.

Y. London, Y. Antman, R. Cohen, N. Kimelfeld, N. Levanon, and A. Zadok, “High-resolution long-range distributed Brillouin analysis using dual-layer phase and amplitude coding,” Opt. Express 22(22), 27144–27158 (2014).
[Crossref] [PubMed]

D. Elooz, Y. Antman, N. Levanon, and A. Zadok, “High-resolution long-reach distributed Brillouin sensing based on combined time-domain and correlation-domain analysis,” Opt. Express 22(6), 6453–6463 (2014).
[Crossref] [PubMed]

Y. Antman, N. Levanon, and A. Zadok, “Low-noise delays from dynamic Brillouin gratings based on perfect Golomb coding of pump waves,” Opt. Lett. 37(24), 5259–5261 (2012).
[Crossref] [PubMed]

A. Zadok, Y. Antman, N. Primerov, A. Denisov, J. Sancho, and L. Thevenaz, “Random-access distributed fiber sensing,” Laser Photonics Rev. 6(5), L1–L5 (2012).
[Crossref]

Y. Antman, N. Primerov, J. Sancho, L. Thévenaz, and A. Zadok, “Localized and stationary dynamic gratings via stimulated Brillouin scattering with phase modulated pumps,” Opt. Express 20(7), 7807–7821 (2012).
[Crossref] [PubMed]

A. Zadok, E. Zilka, A. Eyal, L. Thévenaz, and M. Tur, “Vector analysis of stimulated Brillouin scattering amplification in standard single-mode fibers,” Opt. Express 16(26), 21692–21707 (2008).
[Crossref] [PubMed]

Y. London, Y. Antman, E. Preter, N. Levanon, and A. Zadok, “Brillouin optical correlation domain analysis addressing 440,000 resolution points,” J. Lightwave Technol.34, in press (2016).

Zhang, H.

Zilka, E.

Appl. Opt. (1)

IEEE Photonics Technol. Lett. (2)

I. Sovran, A. Motil, and M. Tur, “Frequency-scanning BOTDA with ultimately fast acquisition speed,” IEEE Photonics Technol. Lett. 27(13), 1426–1429 (2015).
[Crossref]

T. Horiguchi, T. Kurashima, and M. Tateda, “A technique to measure distributed strain in optical fibers,” IEEE Photonics Technol. Lett. 2(5), 352–354 (1990).
[Crossref]

IEEE Trans. Aero. Electron. Sys. (1)

S. W. Golomb, “Two-valued sequences with perfect periodic autocorrelation,” IEEE Trans. Aero. Electron. Sys. 28(2), 383–386 (1992).
[Crossref]

IEICE T. Electorn (1)

K. Hotate and T. Hasegawa, “Measurement of Brillouin gain spectrum distribution along an optical fiber using a correlation-based technique -proposal, experiment and simulation,” IEICE T. Electorn E83-C(3), 405–412 (2000).

J. Lightwave Technol. (3)

Laser Photonics Rev. (1)

A. Zadok, Y. Antman, N. Primerov, A. Denisov, J. Sancho, and L. Thevenaz, “Random-access distributed fiber sensing,” Laser Photonics Rev. 6(5), L1–L5 (2012).
[Crossref]

Light Sci. Appl. (1)

A. Denisov, M. A. Soto, and L. Thevenaz, “Going beyond 1000000 resolved points in a Brillouin distributed fiber sensor: theoretical analysis and experimental demonstration,” Light Sci. Appl. 5(5), e16074 (2016).
[Crossref]

Opt. Express (6)

Opt. Laser Technol. (1)

A. Motil, A. Bergman, and M. Tur, “[INVITED] State of the art of Brillouin fiber-optic distributed sensing,” Opt. Laser Technol. 78, 81–103 (2016).
[Crossref]

Opt. Lett. (3)

Proc. SPIE (1)

F. Gyger, E. Rochat, S. Chin, M. Niklès, and L. Thévenaz, “Extending the sensing range of Brillouin optical time-domain analysis up to 325 km combining four optical repeaters,” Proc. SPIE 9157, 91576Q (2014).
[Crossref]

SICE J. Control Meas. Sys. Integration (1)

K. Hotate, H. Arai, and K. Y. Song, “Range-enlargement of simplified Brillouin optical correlation domain analysis based on a temporal gating scheme,” SICE J. Control Meas. Sys. Integration 1(4), 271–274 (2008).
[Crossref]

Other (3)

Y. London, Y. Antman, E. Preter, N. Levanon, and A. Zadok, “Brillouin optical correlation domain analysis addressing 440,000 resolution points,” J. Lightwave Technol.34, in press (2016).

A. Fellay, L. Thévenaz, M. Facchini, M. Nikles, and P. A. Robert, “Distributed sensing using stimulated Brillouin scattering: towards ultimate resolution,” in Proc. of 12th Optical Fiber Sensors Conference (Optical Society of America, 1997), paper OWD3.
[Crossref]

R. W. Boyd, Nonlinear Optics, 3rd ed. (Academic, 2008).

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Figures (6)

Fig. 1
Fig. 1 Left – calculated normalized magnitude of the stimulated acoustic field as a function of position and time along a 9 m long fiber under test. Only part of the fiber is shown, for better clarity. The BFS of the fiber was taken to be uniform, and the frequency offset between pump and signal was chosen to match that value. The BFS was modified by 30 MHz within a 5.6 cm-wide segment located 3 m from the input end of the pump wave. The signal and pump waves are jointly phase-modulated by a repeating perfect Golomb code with a period of 11 bits and symbol duration of 267 ps. The pump wave is also amplitude-modulated by a single pulse of 30 ns duration. The acoustic field is confined to multiple, discrete and closely-spaced correlation peaks. Due to the short period of the phase code, SBS interactions at neighboring peaks take place with substantial temporal overlap. The acoustic field at the peak which is in spatial overlap with the modified region is considerably weaker than all others. Right – calculated power of the signal wave at the output of the FUT. Red and blue traces correspond to pump pulse durations of 30 ns and 29 ns, respectively (see legend).
Fig. 2
Fig. 2 Blue trace: The result of subtraction between the two calculated traces of the output signal power of Fig. 1(right). The frequency offset between pump and signal was chosen to match the BFS of the fiber outside the modified region. The difference trace recovers the magnitude of individual SBS gain events without ambiguity. The weaker gain event at 105 ns corresponds to SBS in a correlation peak which is in overlap with the modified region. Red and black traces were obtained using the same process, with the frequency offset between pump and signal taken to be 15 MHz and 30 MHz above the BFS of fiber outside the modified region, respectively.
Fig. 3
Fig. 3 Schematic illustration of the experimental setup. SOA: semiconductor optical amplifier; EDFA: erbium-doped fiber amplifier; SSB Mod.: singles side-band electro-optic modulator; Phase mod.: electro-optic phase modulator.
Fig. 4
Fig. 4 Left – example of a pair of measurements of the output signal wave, taken for ν = 10.765 GHz which is close to the BFS of the FUT at room temperature. Only parts of the traces are displayed for better clarity. The sections of the traces displayed are in overlap with a single hot-spot. The pump pulse durations were 30 ns (red) and 29 ns (blue). Both traces consist of series of overlapping SBS gain events. Right – result of the subtraction between the two traces of the left panel. The difference trace consists of a series of amplification events that are unambiguously associated with individual correlation peaks. A single gain event, which corresponds to a correlation peak that is in overlap with the hot-spot, is much weaker.
Fig. 5
Fig. 5 Measured normalized SBS gain (arbitrary units), as a function of correlation peak position and frequency offset between pump and signal waves.
Fig. 6
Fig. 6 Left - Measured Brillouin frequency shift as a function of position. Right – magnified view of the region containing the three local hot-spots.

Tables (1)

Tables Icon

Table 1 Comparison between this work, previous B-OCDA setups and DPP B-OTDA

Equations (4)

Equations on this page are rendered with MathJax. Learn more.

A s ( z=L,t ) A ˜ s ( t )= A s0 n c n rect( tn T phase T phase ) .
A p ( z=0,t ) A ˜ p ( t )= A p0 rect( t T pulse ) n c n rect( tn T phase T phase ) .
Q( z,t )=j g 1 0 t e Γ A ( tt' ) A ˜ p ( t' z v g ) A ˜ s * [ t' z v g +θ( z ) ]dt'.
A s ( z,t ) z + 1 v g A s ( z,t ) t = g 2 Q * ( z,t ) A ˜ p ( t z v g ).

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