Performance and limitations of high brightness Er⁺³-Yb³⁺ fiber sources

Recent development of fiber sources allows the generation of high peak power in the pulsed regime. Coherent LIDAR applications in the eye-safe window are designed with erbium-ytterbium fiber amplifiers. The main limitation to increase the optical power of narrow linewidth signals is the Stimulated Brillouin Scattering (SBS). A dynamic model for these fiber amplifiers is presented, and compared to the stationary model of the non-fluctuating localized source. Design rules are deduced for high brightness power fiber amplifiers. Enlarging the optical mode size increases the SBS threshold. However, fibers can guide several modes leading to a decrease in spatial quality. A detailed analysis of multimode propagation and refractive index profile inhomogeneities and their influence on beam quality has been conducted. Our numerical model has been applied to the design of an all-fiber MOPA source generating 100 μJ per pulse with 180 W peak power. To cite this article: G. Canat et al., C. R. Physique 7 (2006).