Characterization of Brillouin Gratings in Optical Fibers and Their Applications

Dong, Yongkang; Zhang, Hongying; Zhou, Da-Peng; Bao, Xiaoyi; Chen, Liang

doi:10.5772/27077

Cited by 10 publications

(5 citation statements)

References 20 publications

(19 reference statements)

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“…The Brillouin grating-based coherent FMCW reflectometer comprised the conventional coherent FMCW reflectometry setup [10][11][12] for detecting the reflection from a device under test (DUT) and an optical fiber loop [2][3][4][5][6] for generating an acoustic wave or Brillouin dynamic grating in the DUT by counter-propagating pump lights, as shown in Figure 1. The conventional FMCW part was designed to detect the reflection whose optical frequency was down-converted by the Brillouin dynamic grating induced in the DUT.…”

Section: Experimental Setup For the Reflectometermentioning

confidence: 99%

“…The Brillouin-enhanced four-wave mixing induced by counter-propagating pump lights and one probe light produces backward Stokes light at every location in an optical fiber under test [1], which is assumed to be the reflection of the probe light by the acoustic wave or Brillouin dynamic grating generated in the fiber by the two pump lights. Optical time-domain reflectometry (OTDR) has been used to detect the power of the Stokes light as a function of distance while changing the frequency difference between the pump lights to obtain the Brillouin spectrum distribution in the optical fiber [2][3][4][5][6]. A micrometer-scale spatial resolution is indispensable for diagnosing planar lightwave circuits (PLCs) [7] with the same four-wave mixing technique.…”

Section: Introductionmentioning

confidence: 99%

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Theoretical and Experimental Investigation of the Effect of Pump Laser Frequency Fluctuations on Signal-to-Noise Ratio of Brillouin Dynamic Grating Measurement with Coherent FMCW Reflectometry

Kikuchi

Satoh

Kurita

et al. 2021

Sensors

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Signal-dependent speckle-like noise has constituted a serious factor in Brillouin-grating based frequency-modulated continuous-wave (FMCW) reflectometry and it has been indispensable for improving the signal-to-noise ratio (S/N) of the Brillouin dynamic grating measurement to clarify the noise generation mechanism. In this paper we show theoretically and experimentally that the noise is generated by the frequency fluctuations of the pump light from a laser diode (LD). We could increase the S/N from 36 to 190 merely by driving the LD using a current source with reduced technical noise. On the basis of our experimental result, we derived the theoretical formula for S/N as a function of distance, which contained the second and fourth-order moments of the frequency fluctuations, by assuming that the pump light frequency was modulated by the technical noise. We calculated S/N along the 1.35 m long optical fiber numerically using the measured power spectral density of the frequency fluctuations, and the resulting distributions agreed with the measured values in the 10 to 190 range. Since higher performance levels are required if the pump light source is to maintain the S/N as the fiber length increases, we can use the formula to calculate the light source specifications including the spectral width and rms value of the frequency fluctuations to achieve a high S/N while testing a fiber of a given length.

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Section: Experimental Setup For the Reflectometermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Theoretical and Experimental Investigation of the Effect of Pump Laser Frequency Fluctuations on Signal-to-Noise Ratio of Brillouin Dynamic Grating Measurement with Coherent FMCW Reflectometry

Kikuchi

Satoh

Kurita

et al. 2021

Sensors

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“…in Equation 1is obtained by replacing ∆I pr with ∆I p1 and G pr (ν) with G p (ν) in Equation 10, where ∆I p1 and G p (ν) are the mean photocurrent and spectrum of the pump light component ∆E p1 . Since the origin of ∆E p1 is the coherent light from the laser source whose bandwidth is 100 kHz, G p1 (ν) is approximated as a delta function δ(ν-ν p1 ) with ν p1 = (ω p + Ω)/2π and the resultant width of Equation 12becomes the effective width defined by Equation (5). Therefore, we obtain:…”

Section: Current Noise Spectral Densitymentioning

confidence: 99%

“…The Brillouin-enhanced four-wave mixing induced by counter-propagating pump lights and one probe light produces a backward Stokes light in a waveguide under test [1], which is assumed to be the reflection of the probe light by an acoustic wave or a dynamic Brillouin grating excited in the waveguide by the two pump lights. Optical time-domain reflectometry (OTDR) has been used to detect the reflection distribution, or Brillouin grating distribution, while changing the frequency difference between the pump lights to obtain the Brillouin spectrum distribution in an optical fiber [2][3][4][5][6]. A micrometer-scale spatial resolution is indispensable for diagnosing miniaturized optical circuits and modules with the same four-wave mixing technique.…”

Section: Introductionmentioning

confidence: 99%

Signal-to-Noise Ratio of Brillouin Grating Measurement with Micrometer-Resolution Optical Low Coherence Reflectometry

Takada

Satoh

Kawakami

2020

Sensors

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Signal-dependent speckle-like noise was the dominant noise in a Brillouin grating measurement with micrometer-resolution optical low coherence reflectometry (OLCR). The noise was produced by the interaction of a Stokes signal with beat noise caused by a leaked pump light via square-law detection. The resultant signal-to-noise ratio (SNR) was calculated and found to be proportional to the square root of the dynamic range (DR) defined by the ratio of the Stokes signal magnitude to the variance of the beat noise. The calculation showed that even when we achieved a DR of 20 dB on a logarithmic scale, the SNR value was only 7 on a linear scale and the detected signal tended to fluctuate over ±14% with respect to the mean level. We achieved an SNR of 24 by attenuating the pump light power entering the balanced mixer by 55 dB, and this success enabled us to measure the Brillouin spectrum distributions of mated fiber connectors and a 3-dB fused fiber coupler with a micrometer resolution as examples of OLCR diagnosis.

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“…A physical mechanism responsible for dynamic grating inscription strongly depends on the media properties. Acoustic waves enhanced by a stimulated Brillouin scattering (SBS) in optical fibers create a refractive index grating known as Brillouin dynamic grating (BDG) that has recently emerged as a flexible tool for optical processing, microwave photonics and distributed sensing [2][3][4][5][6][7] . The population inversion dynamical gratings (PIDG) inscribed by counterpropagating optical waves in rareearth-doped fibers are responsible for rather slow or even stationary dynamical effects 8,9 .…”

Section: Introductionmentioning

confidence: 99%

Brillouin-like effects in rare-earth-doped bi-directional optical fiber amplifiers

Fotiadi

Коробко

Chapalo

et al. 2023

Nonlinear Optics and Applications XIII

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Characterization of Brillouin Gratings in Optical Fibers and Their Applications

Cited by 10 publications

References 20 publications

Theoretical and Experimental Investigation of the Effect of Pump Laser Frequency Fluctuations on Signal-to-Noise Ratio of Brillouin Dynamic Grating Measurement with Coherent FMCW Reflectometry

Theoretical and Experimental Investigation of the Effect of Pump Laser Frequency Fluctuations on Signal-to-Noise Ratio of Brillouin Dynamic Grating Measurement with Coherent FMCW Reflectometry

Signal-to-Noise Ratio of Brillouin Grating Measurement with Micrometer-Resolution Optical Low Coherence Reflectometry

Brillouin-like effects in rare-earth-doped bi-directional optical fiber amplifiers

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