Final PhD seminar: Towards Rare-earth Doped Chalcogenide Waveguide Amplifiers
Chalcogenide glass waveguide devices have received a great deal of attention worldwide in the last few years on account of their excellent properties and potential applications in mid-infrared sensing and all-optical signal processing. Waveguide propagation losses however currently limit the potential for low power nonlinear optical processing, and the lack of suitable chip integrated MIR sources is one of the major barriers to integrated optics based MIR sensing. One approach to overcome the losses is to employ rare-earth doped waveguides in which the optical gain can compensate the loss, in such a way that the conversion efficiency of nonlinear effects is increased significantly. For infrared applications, the long wavelengths potentially attainable from rare earth transitions in chalcogenide hosts are unique amongst glass hosts. New rare earth doped chalcogenide sources in the mid-infrared range could benefit molecular sensing, medical laser surgery, defence etc.
This final PhD talk focuses on the realisation of optical amplifiers based on rare-earth doped chalcogenide glasses. The talk will cover the useful properties of chalcogenides, the optimisation of the host materials and fabrication methods, leading to the first demonstration of internal gain in an Er doped As2S3 planar waveguide. Also greater than 50% Erbium inversion was achieved for the first time in a chalcogenide host using GeGaSe planar waveguides with 1.5×10-20 ion/cm3 Erbium concentration (>1 dB/cm gain potential), promising future high performance rare-earth doped chalcogenide waveguide amplifiers.