Absorption of an incoherent pump in a double-clad fiber amplifier is analyzed in the paraxial wave approximation. Different inner cladding shapes are considered. A small spiral distortion of an otherwise circular inner cladding shape is shown to enhance the coupling efficiency significantly relative to other geometries.
© 2002 Optical Society of America
(060.0060) Fiber optics and optical communications : Fiber optics and optical communications
(060.2270) Fiber optics and optical communications : Fiber characterization
(060.2320) Fiber optics and optical communications : Fiber optics amplifiers and oscillators
(140.3510) Lasers and laser optics : Lasers, fiber
Dmitrii Kouznetsov and Jerome V. Moloney, "Efficiency of pump absorption in double-clad fiber amplifiers. II. Broken circular symmetry," J. Opt. Soc. Am. B 19, 1259-1263 (2002)