Photoinduced optical integrated circuits and bulk photonic devices in chalcogenide glasses

Chalcogenide glasses are amorphous semiconductors containing a non-oxide group VI element (S, Se or Te) as one of their components. Important properties of these glasses include infrared transparency, high refractive index, low processing temperatures and ease of integration with other optoelectronic components. There are two additional properties that make them attractive candidates for photonic devices, namely, permanent photostructural changes and a novel energy transfer mechanism for pumping rare earth ions doped in the glasses.; In bulk glasses, a photoinduced volume expansion effect is used to demonstrate surface relief gratings and micro-optical lenslets whose heights and feature sizes can be controlled by using a variety of wavelengths and powers. A thin film deposition and treatment process using rapid thermal annealing is found to significantly enhance the structural stability as well as the photoinduced index changes possible in this materials system. Index changes of up to 5% are possible, and low-loss (0.27 dB/cm) single-mode-channel waveguides have been fabricated, whose mode sizes range from 3 mum to 10 mum. This spans the range of mode sizes from a semiconductor diode laser to a single-mode fiber link. This effect has also been used to demonstrate index-tapered waveguides for on-chip mode-size conversion.; Bulk chalcogenide glasses exhibit a novel rare earth pumping mechanism, where the host glass absorbs and then non-radiatively transfers energy to the rare earth ions doped in them. This work has been extended to thin films of these glasses, and the first observation of 1550-nm emission from Er-doped chalcogenide glass film has been reported. This allows pumping over a broad range of pump wavelengths and has potential applications in fabricating optically pumped lasers and amplifiers, which may be pumped transversely as well as longitudinally.; Reliability and stability issues have, for the first time, been studied in this materials system. Preferred regimes of operation are defined, and accelerated aging studies are used to predict device lifetimes.