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

B. S. Vikram; Roopa Prakash; Santosh Aparanji; V. R. Supradeepa

doi:10.1117/12.2546544

2 March 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

B. S. Vikram, Roopa Prakash, Santosh Aparanji, V. R. Supradeepa

Author Affiliations +

Proceedings Volume 11264, Nonlinear Frequency Generation and Conversion: Materials and Devices XIX; 112641M (2020) https://doi.org/10.1117/12.2546544
Event: SPIE LASE, 2020, San Francisco, California, United States

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.

Citation Download Citation

B. S. Vikram, Roopa Prakash, Santosh Aparanji, and V. R. Supradeepa "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", Proc. SPIE 11264, Nonlinear Frequency Generation and Conversion: Materials and Devices XIX, 112641M (2 March 2020); https://doi.org/10.1117/12.2546544

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available

Members: $17.00

Non-members: $21.00 ADD TO CART

PROCEEDINGS
6 PAGES

DOWNLOAD PAPER SAVE TO MY LIBRARY

GET CITATION

RIGHTS & PERMISSIONS

Get copyright permission Get copyright permission on Copyright Marketplace

KEYWORDS

Modulation

Phase modulation

Fiber lasers

Laser scattering

Fiber amplifiers

Optical amplifiers

Scattering

Show All Keywords

Keywords/Phrases

Search In:

Publication Years