Self-focusing threshold of partially coherent light in large mode area fibers

• We give the explicit expression of self-focusing power threshold for partially coherent light in LMA fibers.
• The threshold increases with larger beam quality factor and broader bandwidth.
• The threshold formula also applies for coherent light in LMA fibers.

Coherent property of light is taken into consideration by utilizing Wigner transform method in solving self-focusing threshold of partially coherent light in LMA silica fibers. The formula for self-focusing threshold applicable for both coherent and partially coherent light in LMA silica fibers is derived, which only depends on beam quality factor M2 and bandwidth ΔλΔλ. It can be conveniently used to estimate self-focusing threshold in experiment and design partially coherent high power fiber amplifiers.