Beam Combining And Sbs Suppression In White Noise And Pseudorandom Modulated Amplifiers

Keywords

Coherent beam combining; Phase modulation; PRBS; Stimulated brillouin scattering; White noise

Abstract

White noise phase modulation (WNS) and pseudo-random binary sequence phase modulation (PRBS) are effective techniques for mitigation of nonlinear effects such as stimulated Brillouin scattering (SBS); thereby paving the way for higher power narrow linewidth fiber amplifiers. However, detailed studies comparing both coherent beam combination and the SBS suppression of these phase modulation schemes have not been reported. In this study an active fiber cutback experiment is performed comparing the enhancement factor of a PRBS and WNS broadened seed as a function of linewidth and fiber length. Furthermore, two WNS and PRBS modulated fiber lasers are coherently combined to measure and compare the fringe visibility and coherence length as a function of optical path length difference. Notably, the discrete frequency comb of PRBS modulation provides a beam combining re-coherence effect where the lasers periodically come back into phase. Significantly, this may reduce path length matching complexity in coherently combined fiber laser systems.

Publication Date

1-1-2015

Publication Title

Proceedings of SPIE - The International Society for Optical Engineering

Volume

9344

Document Type

Article; Proceedings Paper

Personal Identifier

scopus

DOI Link

https://doi.org/10.1117/12.2082713

Socpus ID

84931301704 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/84931301704

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