An optimized configuration of large mode field area PMMA photonic crystal fiber with low bending loss: a new approach

Abstract

We propose to design a ytterbium doped two large MFA fiber for high peak power fiber laser and beam delivery application. These fiber has large MFA of 2492 µm2 when kept straight and 1021 µm2 bent over 8 cm radius at a wavelength of 1550 nm. The difference between propagation loss levels of FM and HOMs extend to efficient single mode guidance in the fiber core while bent. This allows further the fiber to make compact high power laser systems. Moreover the optimizing effective MFA of straight and bend fiber can be obtained by a suitable shape of fiber core, missing air holes in the core and the bending orientation which ultimately leads to the guidance a very high optical power. In fact the bend loss on FM and HOM of straight and bend fiber can be estimated by implementing 2D FDTD technique and it is found that, FM bend loss is very small in the order of 10−2 dB/m with bend orientation and the order of 10−3 dB/m with bend radius.