PROJECT TITLE :

Chirped Laser Seeding for SBS Suppression in a 100-W Pulsed Erbium Fiber Amplifier

ABSTRACT:

A pulsed Er/Yb fiber amplifier is seeded with a frequency-chirped diode laser for the purpose of suppressing stimulated Brillouin scattering (SBS), as another to the traditional broadband seed. SBS in the final stage of the amplifier limits the output power. A chirp of Hz/s is seen to extend the SBS threshold by nine times, compared with the case with no chirp. The final stage of the amplifier is modeled with a system of equations that are solved for the laser field, Stokes field, acoustic field, pump power, amplified spontaneous emission power, Yb inversion, and Er inversion, as a operate of and . The experimental and theoretical results are in good agreement. The SBS threshold scales linearly with chirp, when the effective seed linewidth (the product of chirp and fiber transit time) is a lot of bigger than the Brillouin linewidth.