Vikram, BS and Prakash, R and Aparanji, S and Supradeepa, VR (2020) Enhancement of stimulated Brillouin scattering thresholds of high power narrow-linewidth fiber lasers through a simple line-broadening scheme using a combination of sinusoidal and white noise phase modulation. In: Nonlinear Frequency Generation and Conversion: Materials and Devices XIX, 2 March 2020, San Francisco, California, United States.
Full text not available from this repository.Abstract
Narrow linewidth fiber lasers find widespread applications in beam combining, frequency conversion and remote detection. Power scaling of these lasers is mainly limited by Stimulated Brillouin scattering (SBS). Currently, SBS is mitigated through linewidth broadening and/or fibers with enhanced mode area. The latter suffers from problems of beam degradation and modal instability making line broadening the primary technique for SBS suppression. Line broadening can be achieved with phase modulation of lasers using white noise, pseudo-random bit streams or arbitrary waveform generators. The simplest implementation is with white noise source with the latter two requiring greater resources. We recently demonstrated a 10GHz linewidth 0.5kW polarization maintaining fiber laser, where it was observed that the SBS threshold did not directly scale with linewidth. This effect was identified as arising from the slow roll-off of the spectrum in white-noise modulated spectra which seeds the SBS process. The seeding is due to the reflections from the fiber end facet at these broadened linewidths where the spectrum has appreciable power at the Stokes wavelength. This is anticipated to be fundamental limiter for power scaling of narrow linewidth fiber lasers. In this work we overcome these drawbacks through a simple phase modulation scheme that incorporates noise waveforms together with sinusoidal modulation. This enables the spectrum to have sharp roll-off with flatter central region resulting in substantial reduction in seeding of SBS from end facet. With this simple architecture, we demonstrate scaling of SBS limited power by more than 1.5 times over pure noise modulation. © 2020 SPIE.
| Item Type: | Conference Paper |
|---|---|
| Publication: | Proceedings of SPIE - The International Society for Optical Engineering |
| Publisher: | SPIE |
| Additional Information: | Copyright for this article belongs to the SPIE. |
| Keywords: | Fiber lasers; Fibers; Linewidth; Noise generators; Phase modulation; Polarization-maintaining fiber; White noise, Arbitrary waveform generator; Linewidth broadening; Narrow linewidth fiber laser; Pseudo random bit stream; Sinusoidal modulation; Stimulated Brillouin Scattering (SBS); Stimulated Brillouin scattering threshold; Substantial reduction, Stimulated Brillouin scattering |
| Department/Centre: | Division of Interdisciplinary Sciences > Centre for Nano Science and Engineering |
| Date Deposited: | 22 Sep 2021 09:59 |
| Last Modified: | 22 Sep 2021 16:09 |
| URI: | http://eprints.iisc.ac.in/id/eprint/65445 |
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