title: Extremely large-mode-area photonic crystal fibre with low bending loss.
abstract: We report on the design of a novel flexible very large mode area photonic crystal fibre for short pulse high peak power fibre laser and beam delivery applications. This fibre has an extremely large mode area exceeding 2500 microm(2) when kept straight and over 1000 microm(2) when bent over a 10 cm radius at a wavelength of 1064 nm. In addition our fibre exhibits very small fundamental mode bending loss below 10(-2) dB/m. The large difference between the propagation loss levels of fundamental and higher order modes forces efficient single-mode guidance in the fibre core while bent. This allows using the fibre to build compact high power laser systems. The paper further explores the major features of this fibre including: the dependence of the mode field area on the fibre core shape, the influence of the bending radius and of the bending direction as well as the impact of manufacturing tolerances on the fibre specifications.
authors: Wrocław University of Technology, Institute of Telecommunications, Teleinformatics and Acoustics, Wybrzeze Wyspiańskiego 27, 50-370 Wrocław, Poland. marek.napierala@pwr.wroc.pl
authors: Marek
authors: M
authors: Napierała
authors: Tomasz
authors: T
authors: Nasiłowski
authors: Elzbieta
authors: E
authors: Bereś-Pawlik
authors: Francis
authors: F
authors: Berghmans
authors: Jan
authors: J
authors: Wójcik
authors: Hugo
authors: H
authors: Thienpont