A segmented heterostructure cladding fiber designed for extreme large mode area

Abstract

A segmented heterogeneous cladding (SHC) fiber was proposed in this work to obtain extreme large mode area. The mode propagation characteristics of the SHC fiber was analysed in detail, including loss coefficient, effective mode area and transverse mode discrimination et al. The research results show that the fiber parameters such as the central angle θ of cladding 2, the wavelengthλ, the fiber core radius r and the refractive index n2 of cladding 2 all have effects on loss coefficient and effective mode area, but transverse mode discrimination is almost unaffected. When r is 150 μm, the mode area is up to 34,343 μm2. The principle of single mode operation for the SHC fiber laser was also suggested. Thus, the SHC fiber can be designed for extreme large mode area and applied in high power fiber lasers.