Proposal and design of sectorial cladding optical fibre for large-mode-area, single-mode operation

A novel design of single-mode microstructured optical fibre with large-mode-area is proposed. The proposed fibre is composed of a circular-core, which is surrounded by three sectorial low-index segments and three supporting bridges. For sufficiently wide bridges, the high-order modes in the fibre will be induced to the bridges and leaked out, whereas the fundamental mode is confined by the sectorial low-index segments. In addition, the losses of the fundamental mode can be reduced sufficiently by increasing the radius of the sectorial segments. Numerical investigations demonstrate that single-mode operation with ultra-large mode-area and low confinement loss can be achieved in the proposed fibre