In this paper Tm/Yb doped microspheres have been successfully created through melting the ends of fibre cores etched
from single mode Tm/Yb fibres designed and fabricated specifically for the laser emission centred at mid-infrared region.
When coupled with a fibre taper, a microsphere fibre laser cavity can thus be configured creating a system when pumped
by a ~1600nm laser source using a monochromator to monitor the spectral characteristics of the laser output produced.
The performance and characteristics of the Tm/Yb microsphere lasers are discussed in detail in the paper. The laser has
shown low threshold in terms of the pump power making it well suited to potential optical fibre sensor applications.
Some preliminary results obtained from research into the development of a fibre-coupled microsphere laser-based
system, with potential for sensor use, are discussed in this paper. Based on a theoretical analysis of micro-cavity laser
configurations and of the design of the laser components used, an experimental setup has been created to optimize the
coupling efficiency between the microsphere and the wave-guiding tapered fibre and thus to show the potential for a low
threshold compact laser system as a source for a compact gas sensing device.