Spectroscopic Studies of Rare Earth Doped Phosphate Glasses

Glass is the most important substrate material suitable for fabrication of passive and active integrated optical components. The refractive index of a glass substrate is very close to that of the optical fibers (n=1.48), which minimizes the coupling losses between glass waveguides and optical fibers. Glass has excellent transparency in the visible and near infrared spectral regions and can easily be made in different sizes and shapes with very high homogeneity. As an amorphous material distinct from crystals, it is easier to produce polarization insensitive integrated optical components in glass. In addition, Glass has a high threshold to optical damage; it is mechanically very rigid and relatively inexpensive. Glass is also suitable host for rare earth ions. This has allowed for the fabrication of optical amplifiers and lasers.