Nanostructured active and photosensitive silica glass for fiber lasers with built-in Bragg gratings

Abstract

A nanostructured core silica fiber with active and photosensitive areas implemented within the fiber core is demonstrated. The photosensitivity, active and passive properties of the fiber can be independently shaped with this new approach. We show that discrete local doping with active ions in form of nanorods allow to obtain effective laser action as in case of continuous distribution of the ions in the core. Co-existing discrete photosensitive nanostructure of germanium doped silica determine single-mode performance and allow inscription of highly efficient Bragg grating over the entire core area. Each nanostructure do not degrade performance of other one since physical interaction between active and photosensitive areas are removed. As a proof of concept, we have designed and fabricated the nanostructured, ytterbium single-mode silica fiber laser with the Bragg grating inscribed in the entire core area. We demonstrated fiber laser with good quality of generated laser beam (M2=1.1) with lasing efficiency of 44% and inscribed Bragg grating with 98.5% efficiency and -18 dB contrast.

Phosphate glass nanostructured core fiber for laser with dual wavelength emission

“…We used nanostructuring method for the fiber development, which we successfully applied for fabricating optical fibers and optical components, e.g. fiber with the parabolic profile of gradient index in the core [14], active ytterbium doped fibers made of phosphate [15] or silica [16] [17], and GRIN micro-vortex [18].…”