Erbium and hydrogen implantation into glass for optical device applications.

A material which exhibits a refractive index change on exposure to ultra violet light is obtained when germania doped silica is heated in a hydrogen atmosphere. This phenomena is called photosensitivity. Bragg gratings, which are useful for the fabrication of feedback mirrors in optical amplifiers and as optical filters, can be readily fabricated by exposing a photosensitive waveguide to an ultraviolet interference pattern. Ion implantation, which allows localised substrate doping, is a useful means of introducing hydrogen when compared to thermal annealing. In this thesis, it is demonstrated for the first time that hydrogen implantation into heated germania doped silica yields a photosensitive material. The optical properties of arsenic doped silica (ASG) waveguides allow the fabrication of single mode waveguides of height 2 mum, a depth which implanted erbium ions may readily penetrate. Erbium implanted ASG waveguides are therefore a suitable candidate for use as the amplifying region in waveguide optical amplifiers. In this thesis, ion implantation is used to introduce erbium atoms into ASG waveguides, and the optical characteristics of the implanted waveguides assessed. The implanted waveguide optical propagation loss, the 1550 nm fluorescent lifetime decay, and the optical propagation loss of erbium implanted ASG waveguides was measured as a function of erbium dose. These experiments are required to determine the suitability of erbium implanted ASG waveguides for the fabrication of optical amplifiers. It was demonstrated that erbium fluorescence lifetimes of up to 10 ms and an optical absorption in the region of 2 dB/cm to 4 dB/cm at a wavelength of 1550 nm could be obtained whilst maintaining a low waveguide optical propagation loss. These results suggest that erbium implanted into ASG waveguides is suitable for the fabrication of the active region of optical amplifier devices.