Abstract-The mid-IR spectral range is of particular interest for two main reasons: many molecules exhibit signature optical absorptions in this wavelength range and specific transmission windows within these wavelengths are available in the Earth's atmosphere. Options for compact, reliable, high power mid-IR optical sources are currently rather limited by the difficulty of finding host materials that are both transparent in the mid-IR wavelengths range and sufficiently stable, robust and easy to fabricate. In this paper the relevant glass host materials suitable for the development of mid-IR coherent sources based on rare earths doping are briefly reviewed. The current state of the art in mid-IR fiber laser and supercontinuum sources is also presented.