An investigation into waveguiding and light emission from erbium-doped hosts compatible with silicon technology

A computer program is developed which enables the simulation of the propagating optical modes in a wide variety of waveguide structures. This existence and loss of leaky modes are also handled, as many waveguides produced on silicon substrates are of this type. The use of this program is then demonstrated with examples, including the design, simulation, fabrication and testing of novel ARROW waveguides.The possibility of incorporating erbium into single-crystal silicon by thermal diffusion is investigated using a variety of diffusion ambients. During this work, a novel silicon chamber was developed in order to provide a contamination-free diffusion environment. It is shown that while repeatable diffusion profiles can be obtained under an oxygen/argon ambient, the rate of diffusion is too low to be of use, even at 1315oC.Erbium-doped silicon monoxide is shown to produce sharp-line photoluminescence when optically excited at energies above the band-gap. This material, which is produced by thermal co-evaporation, is then characterised in terms of its spectroscopic properties. Excitation of the erbium is via the recombination of electron-hole pairs at erbium sites and as such is different to the normal route of direct optical absorption. It is found that thermal quenching of the photoluminescence is not a dominant factor at room-temperature, as is the case for erbium-doped silicon, and a relatively high concentration of active erbium ions may be incorporated by using the appropriate anneal.Finally, several silicon-based materials are compared with respect to their relative merits as hosts for erbium ions. The concentration of active ions which might be required to allow lasing are presented for each material. It becomes clear from this exercise that none of the materials appear to offer excellent properties for making a laser. Nevertheless, erbium-doped silicon carbide, while not yet extensively studied, represents the best chance of success.