Abstract

Stimulated Brillouin scattering (SBS) is the major factor that limits maximum peak power of single-frequency pulsed fiber laser systems. It should be noted that in the all-fiber format it is the passive fibers at the amplifier output (used as pigtails in isolator and etc) are those component that often has the smallest SBS threshold [1]. Thus, development of large mode area (LMA) passive fibers with increased SBS threshold becomes an important task. One of the successful approaches is tailoring acoustic profile of the fiber to “push” out of the core acoustic wave and reduce its overlap with optic fields [2]. This approach requires doped outer cladding [3] or a very short wavelength cut-off [4], which is hardly compatible with passive LMA fibers.

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