Analytical approach of Brillouin amplification over threshold

Brillouin fiber lasers (BFLs) are a promising optical source technology for industrial and academic purposes that have experienced continuous progress in recent years. Currently, part of this development is focused on delivering laser solutions with low resonator loss, relatively low pump threshold, high efficiency, very small linewidth, and multi-wavelength architecture. In this perspective, this study employs an accurate numerical model based on an analytical solution to investigate the effect of the pump’s spectral linewidth on BFLs working both in single and cascaded multi-wavelength configurations. Output powers, thresholds, and the Stokes lines number simulated are analyzed here using a standard single-mode optical fiber as the Brillouin gain medium. The numerical results obtained not only allow identifying the regions of the pump’s spectral linewidth in which there is greater, moderate, or even no suppression of the stimulated Brillouin scattering inside the laser cavity but also provides a deep understanding of the internal dynamics of the BFLs cavities.

Section: Simulation Structurementioning

confidence: 99%

Numerical analysis of the pump’s spectral linewidth impact on single and multi-wavelength Brillouin fiber lasers

Silva¹,

Castellani²

2021

“…Stimulated Brillouin scattering (SBS) is a useful threeorder nonlinear optical effect. Up to now, this effect has attracted wide attention owing to its broad applications, such as in phase conjugation mirrors [8], pulse compression and amplification [9][10][11][12], beam combination [13], beam cleanup in multi-mode fiber lasers [14], and so forth. Besides the above-mentioned applications, optical energy and power limiting using SBS are what attract our attention [15][16][17].…”

Section: Laser Physicsmentioning

confidence: 99%

Optimising of the material and laser parameters for high-power laser spatial beam smoothing based on stimulated Brillouin scattering

Zhu

Yang

et al. 2019

In this paper, we numerically study the influence of material and laser parameters on laser spatial beam uniformity improvement based on stimulated Brillouin scattering (SBS). Owing to the intensity dependent property of SBS, the higher intensity parts of the laser beam experience a deep reflection, while the other parts transmit through the medium with weak reflection. Then, the uniformity of the input laser beam is improved. A single frequency laser with a 20th order super-Gaussian shaped output pulse was used as the pump. Five typical liquid materials were adopted as the Brillouin medium for comparison. The laser wavelength was set to 527 nm and 1053 nm; and the pulse duration was set to 3 ns and 5 ns, respectively. The numerically calculated results indicate that low gain coefficient and short phonon lifetime mediums (such as FC-70) are more suitable for the above-mentioned laser beam smoothing scheme. Meanwhile, short wavelength and pulse duration would be helpful for laser beam uniformity improvement. The energy efficiency is above 90% when the laser beam uniformity is greatly improved with an optimized input laser intensity. The calculated results are quite useful for high-power laser applications.

“…Stimulated Brillouin scattering (SBS) is a useful nonlinear optical effect happening in high-power single frequency lasers. Over the past decades, SBS has attracted wide attention owing to its broad applications, such as SBS phase conjugation mirror [7], pulse compression [8,9], beam combination [10], Brillouin amplification [11,12], beam cleanup in multi-mode fiber lasers [13], and so forth. Besides the above-mentioned applications, Lu et al reported a special application called optical energy and power limiting by using SBS [14][15][16].…”

Section: Introductionmentioning

confidence: 99%

High efficiency laser spatial beam smoothing based on stimulated Brillouin scattering

Zhu

et al. 2019

In this paper we proposed and numerically demonstrated a novel scheme for spatial beam smoothing of high-power lasers based on stimulated Brillouin scattering (SBS). With the intensity dependent property of SBS, the higher intensity parts of the laser beam are reflected to a great extent when the other parts are transmitted through the medium with weak reflection. Then, the inputted non-uniform high-power laser beam is smoothed. As a numerically simulation experiment, the beam smoothing property of the proposed scheme was calculated in this paper. A pulsed single frequency laser was used as the pump, whose output pulse is 20th order super-Gaussian shaped with a duration of 3 ns, a beam diameter is 40 mm and a wavelength of 527 nm. The heavy fluorocarbon FC-40 was used as the nonlinear medium. The numerically calculated results indicate that the laser intensity modulation index can be greatly pulled down after passing through the Brillouin medium with a suitable laser intensity. The energy efficiency is above 90% when the laser beam is smoothed to the greatest extent.