A holmium non-linear polarisation rotation (NLPR) all-fibre mode-locked laser was characterised. The radiofrequency (RF) spectrum of the pulsed train output was used as an automation metric. Non-ideal pulsing behaviour was corrected by changing the intracavity polarisation state using actuators in an electronic polarisation controller. The optimum cavity produced mode-locked pulses with a central wavelength of 2.061 μm and an 8.7 nm optical full-width-at-half-maximum (FWHM).
CO2 laser processing facilitates contamination free, rapid, precise and reproducible fabrication of devices for high power fibre laser applications. We present recent progress in fibre end-face preparation and cladding surface modification techniques. We demonstrate a fine feature CO2 laser process that yields topography significantly smaller than that achieved with typical mechanical cleaving processes. We also investigate the side processing of optical fibres for the fabrication of all-glass cladding light strippers and demonstrate extremely efficient cladding mode removal. We apply both techniques to fibres with complex designs containing multiple layers of doped and un-doped silica as well as shaped and circularly symmetric structures. Finally, we discuss the challenges and approaches to working with various fibre and glass-types.