A low confinement loss double-photonic crystal fibre over 850 nm bandwidth with 26 orbital angular momentum modes transmission.

In this paper, a new double-photonic crystal fibre (D-PCF) is proposed and numerically investigated, result shows that can support angular momentum (OAM) mode transmission up to 26. Based on As2S3 substrate, the proposed D-PCF is composed of three well-ordered air-hole rings in the cladding and another several air-hole rings at the centre. Due to the large effective index difference greater than 10−4 between eigenmodes, OAM can be well separated with the proposed D-PCF. In addition, the confinement loss of less than 7 × 10−9 dB/m for all eigenmodes is obtained with wavelengths spanning from 1.25 to 2.1 µm, where the optical wave can be confined closely within the core of D-PCF. With these beneficial properties, the designed D-PCF could enable large-capacity transmission in high-speed communications. [ABSTRACT FROM AUTHOR]