Generation of phase singular optical beams in microstructure optical fibers

A realizable concept on the generation and propagation of phase singular optical beams in high refractive index As2S3 Chalcogenide five ring hexagonal triangular lattice microstructure optical fiber (MOF) is presented. The hexagonal lattice structure with missing air holes in the first ring allows the generation of optical vortices which has been investigated. Variations in fiber mode characteristics along the length of the MOF are shown and it is demonstrated that a vortex mode repeats itself after an optimized fiber length. Numerical analysis has also been carried out for other optical properties such as the effective refractive index, V-parameter, total dispersion and loss to investigate the effect of fiber design parameters on the critical characteristics. The design freedom of the MOF enabled to achieve a low value of total dispersion variation (< 40 nm/ps km) over a range of 650 nm optical bandwidth. Moreover, the vortex mode has a small confinement loss (< 0.029 dB/m) up to the range of 1800 nm. Our results pave the way to applications in active and passive MOF fiber based sources and devices, optimized tweezers high-resolution imaging and sensing application.