ABSTRACT
In this chapter, the authors survey the present state of the art from a materials viewpoint, while updating the account of Hall and Weber. They describe various glass systems and technologies that have been employed for the fabrication of doped glass waveguide lasers. Then, the authors review optical properties of the rare-earth ions in the various host glasses that have so far been employed for waveguide fabrication. Of the oxide glasses, high-silica glasses employed in the telecommunications industry for optical fiber fabrication are by far the most commonly used as a host waveguide for rare-earth ions. Single mode fibers were fabricated using the rod-in-tube method which, despite flame polishing of the glass constituents, resulted in a waveguide optical loss of 4 dB/m due to scattering by defects at the core/cladding interface. The utilization of waveguide geometries for rare-earth-doped glass lasers and amplifiers confers a number of benefits compared with bulk systems.
