Novel waveguide techniques and devices in rare-earth doped glass and rare-earth indiffused lithium niobate.

Abstract

The research described in this thesis focuses on the development of novel fabrication techniques and new devices in rare-earth doped glasses and lithium niobate substrates. These two substrate are among the most promising materials for the development of complex, highly efficient, integrated optical devices. We demonstrate the first Yb-doped glass waveguide laser fabricated using the ion exchange technique. Characterization of the glass and waveguides, along with device performance predictions based on laser modeling, are reported. Observations of intrinsic optical bistability in rare earth-doped waveguides are also described. We investigate a direct-write method of fabricating waveguides in glasses using femtosecond laser pulses. The direct-write method has the potential to provide a very simple, reliable and extremely convenient way of fabricating waveguides and complex three-dimensional structures in a wide variety of glasses. We report the first demonstration of a directly written waveguide amplifier in a rare earth-doped glass and characterize both the refractive index structure and losses of some directly written waveguides. Fine period gratings are also fabricated and characterized. The last portion of this thesis is concerned with active and parametric devices in rare earth-doped lithium niobate. The annealed proton exchange (APE, a waveguide fabrication technique) technique, along with rare-earth indiffusion, is used to demonstrate waveguide lasers in Nd-indiffused lithium niobate. Additionally, we report experimental data on the implementation of a ferroelectric periodic poling technique using an external electric field and the subsequent fabrication of APE waveguides in these periodically poled substrates. The integration of APE waveguides and periodically poled lithium niobate (PPLN) with the rare earth-indiffusion process is explored and devices based on this integration are proposed.