Frequency pulling in a Brillouin fiber ring laser

In this work, we present an enhanced design for a Brillouin ring laser (BRL), which employs a double resonant cavity (DRC) with short fiber length, paired with a heterodyne-based wavelength-locking system, to be employed as a pump-probe source for Brillouin sensing. The enhanced source is compared to traditional long-cavity pump-probe source, showing a significantly lower relative intensity noise (~-145 dB/Hz in the whole 0-800 MHz range), a narrow linewidth (10 kHz), and large tunability features, resulting in an effective pump-probe source in BOTDA systems, with an excellent pump-probe frequency stability (~200 Hz), which is uncommon for fiber lasers. The enhanced source showed an improved signal-to-noise ratio (SNR) of about 22 dB with respect to standard BRL schemes, resulting in an improved temperature/strain resolution in BOTDA applications up to 5.5 dB, with respect to previous high-noise BRL designs.

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“…2. In mode hopping, thermal noise and vibrations alter the cavity free spectral range (FSR), causing a shift in the dominant lasing mode [22]. In…”

Section: Double Rementioning

confidence: 99%

Analysis of enhanced-performance fibre Brillouin ring laser for Brillouin sensing applications

Rossi¹,

Marini²,

Bastianini³

et al. 2019

Opt. Express

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“…In practical DRC BRL, the lasing stability of is highly sensitive to frequency detuning of pump resonance due to fluctuations of the cavity length [6] induced i.e. by environmental vibrations and thermal instabilities, and also by the combination of Kerr effect and mode pulling [7]. DRC BRL lasing can be stabilised by a variety of techniques such as those that applies feedback on the cavity length [8] or on the pump wavelength [9].…”

Section: Wavelength Locking Scheme For Drc-brlmentioning

confidence: 99%

Enhanced-performance fibre Brillouin ring laser for Brillouin sensing applications

Marini¹,

Rossi

Bastianini³

et al. 2018

26th International Conference on Optical Fiber Sensors

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“…The frequency pulling can be derived by integrating the imaginary part of the differential equations describing the evolution of the electric fields of the waves circulating inside the ring resonator under appropriate boundary conditions. The total frequency pulling AuZ" and AulSBS calculation for the pump and the first Stokes waves is done in [21] and only the final results are given here where DUB is the Brillouin gain linewidth, A y is the difference in frequency between the Brillouin gain center (of the gain provided by the circulating pump) and the cavity resonant mode for the first Stokes wave, Au2 is the difference in frequency between the Brillouin gain curve center (of the gain provided by the first Stokes wave) and the cavity resonant mode for the second Stokes wave and Au, is the linewidth of the cold ring resonator. I, is defined by (l), g b is the Brillouin gain coefficient and L the fiber length.…”

Section: Kerr and Frequency Pulling Effectsmentioning

confidence: 99%

Frequency stability of a Brillouin fiber ring laser

Nicati

Toyama

Shaw

1995

J. Lightwave Technol.

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This study shows theoretical and experimental results on three main effects determining the frequency stability of a Brillouin 6ber ring laser, namely: the temperature effects and the nonlinear Kern and frequency pulling effects. The oscillation frequency in a Brillouin Fiber Ring Laser is determined mahly by the axial mode of the cold resonator located under the Brillouin gain curve that experiences the highest gain. This oscillation frequency is therefore temperature dependent since both the Free Spectral Range (FSR) and the gain curve center depend on the temperature. The FSR variation gives rise to a continuous lasing frequency variation while the gain curve shift leads to mode hopping. In addition to these temperature effects, the nonlinear Kerr effect and the mode pulling effect will also slightly shift the lasing frequency away from the resonant frequency of the cold resonator. The Kerr effect depends only on the pump power, while the mode pulling effect depends on both the pump power and the relative location between the lasing mode and the gain curve center. The results of this study are useful in many BFRL applications such as Brillouin fiber-optic gyroscopes, microwave generators and frequency shifters. I. I NTRODUCTION TIMULATED Brillouin Scattering (SBS) is a nonlinear S process that produces a gain in the backward direction in optical fibers. Although it can be detrimental in coherent optical communication systems [l], [2] it found many applications such as selective canier amplification [3], distributed temperature sensing [4], characterization of fiber strain [5], and Brillouin fiber lasers [61, [71.Because of its low laser threshold a Brillouin fiber ring laser (BFRL) using a high-finesse fiber ring resonator is especially attractive and it has been used as a narrow-linewidth fiber laser [8], a microwave frequency generator [9]. and a Brillouin fiber ring gyroscope (BFOG) [lo]-[ 121. The previous studies on BFRL clarified the laser threshold condition [7] and the functional form of the circulating Stokes intensity as a function of the pump intensity [13], [14]. It was also found that at only four-times the threshold the circulating firstorder Stokes wave becomes strong enough to support, in turn, the second-order Stokes wave lasing in the ring resonator. At eight-times the threshold the third-order Stokes wave begins lasing. The presence of higher-order Stokes waves defines operating windows of a BFRL. For example, the first window is defined as the range where only the first Stokes wave is lasing, the second window where upto the second Stokes . IEEE Log Number 9412283.waves are lasing, and so on. The generation of these multiple Stokes waves in a BFRL is treated in [14] including the threshold conditions and the functional forms of circulating intensities for higher-order Stokes waves. The oscillation frequency in a BFRL is mainly determined by the axial mode of the cold resonator located under the Brillouin gain curve that experiences the highest gain. This oscillation frequency depends on the...

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Frequency pulling in a Brillouin fiber ring laser

Cited by 25 publications

References 9 publications

Analysis of enhanced-performance fibre Brillouin ring laser for Brillouin sensing applications

Analysis of enhanced-performance fibre Brillouin ring laser for Brillouin sensing applications

Enhanced-performance fibre Brillouin ring laser for Brillouin sensing applications

Frequency stability of a Brillouin fiber ring laser

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