Localized and stationary dynamic gratings via stimulated Brillouin scattering with phase modulated pumps

Antman, Yair; Primerov, Nikolay; Sancho, Juan; Thévenaz, Luc; Zadok, Avi

doi:10.1364/oe.20.007807

Cited by 72 publications

(84 citation statements)

References 34 publications

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“…The underlying principle of localizing the SBS interaction through coding of pump and probe waves is described with mathematical rigor elsewhere in another context 12 . A more intuitive explanation will be described here.…”

Section: Principle Of Operationmentioning

confidence: 99%

“…A more intuitive explanation will be described here. Both Brillouin pump and signal waves are jointly phase-modulated by a common binary pseudo random bit sequence (PRBS), whose symbol duration T is much shorter than the acoustic damping time τ 12 . The modulation phase within each symbol assumes a value of either 0 or π, with equal probabilities.…”

Section: Principle Of Operationmentioning

confidence: 99%

“…Suppose the phase modulation is synchronized so that the two waves are of equal phases at their respective entry points. The instantaneous driving force for the SBS acoustic field generation is proportional to the product of the pump wave envelope and the complex conjugate of the signal wave envelope 5,12 .…”

Section: Principle Of Operationmentioning

confidence: 99%

“…, where g v is the group velocity of light in the fiber 12 . In all other locations, the driving force for the acoustic field is randomly alternating in sign on every symbol duration T τ << .…”

Section: Principle Of Operationmentioning

confidence: 99%

“…The range of unambiguous measurement scales with the length of the PRBS code, and can therefore be made arbitrarily long. This technique had recently been employed in the generation of localized dynamic acoustic gratings in polarization maintaining (PM) fibers, implementing variable delay setups 12 and tunable microwave-photonic filters 13 . * Avinoam.Zadok@biu.ac.il Tel.…”

Section: Introductionmentioning

confidence: 99%

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High-resolution Brillouin fiber sensing using random phase coding of the pump and probe waves

et al. 2012

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Distributed temperature measurements with 1.2 cm resolution based on stimulated Brillouin scattering (SBS) in standard fibers are reported. High resolution is achieved by phase-coding both pump and probe waves with a high-rate, pseudorandom binary phase code. The SBS interaction is effectively confined to narrow correlation peaks. The separation between adjacent peaks, signifying the unambiguous measurement range, scales with the length of the modulation code and can therefore be made arbitrarily long. Measurements were performed over 40 meters of fiber, or 3300 resolution points. The technique is applicable to distributed measurements of birefringence and Brillouin frequency shift over polarization maintaining fibers.

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Section: Principle Of Operationmentioning

confidence: 99%

Section: Principle Of Operationmentioning

confidence: 99%

Section: Principle Of Operationmentioning

confidence: 99%

Section: Principle Of Operationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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High-resolution Brillouin fiber sensing using random phase coding of the pump and probe waves

et al. 2012

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Random‐access distributed fiber sensing

Zadok

Antman

Primerov

et al. 2012

Laser & Photonics Reviews

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Optical sensing offers an attractive solution to the societal concern for prevention of natural and human-generated threats and for efficient use of natural resources. The unprecedented properties of optical fibers make them ideal for implementing a 'nervous system' in structural health monitoring: they are small, low-cost and electrically and chemically inert. In particular, the nonlinear interaction of stimulated Brillouin scattering allows for the distributed measurement of strain and temperature with tens of km range. In this work, a novel, radar-inspired technique for random-access Brillouin scattering-based sensors is shown, making a significant step towards a real optical sensing nerve. The method selectively addresses each fiber segment as a distinct sensing element in a synaptic neuronal system. The measurement principle relies on phase-coding of both the Brillouin pump and signal waves by a high-rate, pseudo-random bit sequence. Temperature measurements with 1 cm resolution are reported. The measurement range is scalable to several km. The precision localization of disturbances has been a mainstay of radar systems since WW-II. A widely employed radar technique relies on the transmission of long sequences of short pulses [1], and their subsequent processing by a pre-designed matched filter at the receiving end. The filtering procedure compresses the sequence of pulses to a temporally-narrow impulse response function, which provides high resolution together with a large signal to noise ratio [1]. Matched filters in radars are realized by correlating the received radar echoes against a replica of the transmitted sequence, which was stored as a reference. The correlation, in turn, is implemented either through ratio-frequency, electrical analogue mixing or via digital signal processing. Correlation coding has been introduced to Rayleigh scattering-based optical time-domain reflectometry, as early as 1989 [2]. In our work, we carry over the principle of match-filtering long pulse sequences to the realm of fiberoptic sensing [3][4][5][6][7], and use it for the unambiguous probing of a random locale. Stimulated Brillouin scattering (SBS) is an ideally suited platform for such random-access sensing system: not only is it inherently dependent on both strain and temperature [8][9][10][11][12], it also allows for the realization of correlation-based matched filtering of pulse sequences directly in the optical domain, as will be described in detail. LETTER ARTICLE RandomIn stimulated Brillouin scattering (SBS), a relatively intense pump wave interacts with a counter-propagating signal wave, which is detuned in frequency [8]. The combination of the two waves generates an intensity beating pattern, whose frequency equals the difference Ω between the two optical frequencies. Through electrostriction, the intensity beat introduces an acoustic wave, which in turn leads to a traveling grating of refractive index variations, due to the photo-elastic effect. The traveling grating can couple optical power between ...

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