Manufacturing high purity chalcogenide glass

Chalcogenide materials are finding increasing interest as an active material in next generation optical and electronic devices. There wide range of properties, ranging from photosensitivity, ability to host rare earth ions, electrical conductivity, phase change, exceptional optical non-linearity's to name only a few are fueling this interest. Moreover, the ability to synthesize these materials in numerous forms as diverse as 2D monolayers, microspheres, optical fibres, nanowires, thin films as well as bulk glass ingots of over a kilogram in size ensures their application space is vast.We began preparation of chalcogenides, largely based on sulphides, in 1992 and since then have built up an extensive capability for their purification, synthesis and fabrication in various forms. A key aspect of this facility is the ability to process in a flowing atmosphere of hydrogen sulphide which provided the capability of synthesis from elemental, oxide or halide precursors, processing through various chemical vapour deposition reactions as well as post purification. In this talk we describe the range of materials we synthesize highlighting high purity sulphide bulk glass and transition metal di-chalcogenides for electronic applications, crystalline semiconductors for solar cell applications, low power phase change memory devices, switchable metamaterial devices as well as traditional chalcogenides glass and optical fibre

Fabrication of lead-gallium-bismuth (PGB) optical fibre for mid-infrared nonlinearity applications

Lead-gallium-bismuth (PGB) is a non-silica based glass that can be used in the fabrication of optical fibre with high nonlinearity, low transmission loss, high thermal stability, and a broad transparency window. With a nonlinearity two orders higher than that of the fluoride based fibres, it has attracted much attention worldwide for its potential application in the mid-infrared region, particularly for applications such as supercontinuum generation. The fabrication process of PGB optical fibre is immature, leading to relatively high transmission loss and limiting the output average power to a few hundreds of milliwatts. However due to its intrinsic advantages such as high nonlinearity, high thermal stability, and low transmission loss, there is huge potential to achieve a higher output power by further improving the fibre fabrication processes. In this paper, we document the design and demonstration of a PGB optical fibre fabrication aimed for the delivery and nonlinear applications in the mid-infrared region. Fabrication steps from glass melting, preform making and fibre drawing will be covered in detail. By optimizing each of the fabrication steps, we expect to be able to produce PGB optical fibres suitable for supercontinuum generation and other nonlinear processes in the mid-infrared region