Over the last few years, mid-IR sources have gained an enormous interest due to their societal impact as most of the organic and inorganic molecules have their strong fundamental absorption lines in this electromagnetic spectrum. Although, a good amount of research has been carried out for the generation of the tunable mid-IR sources, but currently available laser sources are tunable to only few hundred nanometers. This suggests that a large number of lasers in different wavelength regimes to be needed in order to cover a broad mid-IR region and this become an expensive deal. The objective of this book is to provide a detailed overview of a new technique to build mid-IR sources with tunability of upto 4000 nm in a single fiber-optic system. For this purpose, the optical parametric amplification and supercontinuum generation processes are exploited in the chalcogenide glass based fibers and PCFs for the generation of mid-IR radiation in the CW and pulse regime with added feature of tunability. Since the tunable lasers are quite expensive, therefore, the proposed methodology to achieve broadly tunable mid-IR source may be economically cheaper and relatively better solution.