Crystalline GaSb-core optical fibers with room-temperature photoluminescence
Molten-core fibers with a semiconductor core have been enhanced by laser annealing, with the ultimate aim of making improved infrared fiber laser sources. Song and colleagues have developed a technique in which GaSb pellets contained within a Duran or AR-glas (tradenames) glass cladding are drawn to fiber. While these molten-core fibers have been extensively explored with Group IV elements, there has been limited work on III-V semiconductor core fibers. Fibers fabricated with this molten-core method are then annealed with a CO2 laser source to form single crystalline regions within the core, drawing excess antimony away from the core region. Careful control over the cooling rates while monitoring the emission from the fiber minimizes residual stress in the core, allowing for enhanced luminescence at a wavelength similar to that of the bulk material. This is the first demonstration of strong room-temperature luminescence, with this technique showing promise for future development of infrared laser sources.