ABSTRACT
Dielectric planar waveguides have the potential to be one of the key power-scaling architectures for laser sources. Detailed in this chapter are the general approaches available for exciting an active core region and subsequent state-of-the-art methods to extract the stored energy as laser output. With a focus on diode-laser pumping, the possible pump-coupling methodologies are reviewed and associated implications for the management of the waste heat discussed. Due to the asymmetry of the gain region of the planar-waveguide, mode-selection techniques are required to control the spatial quality of the laser output. Several novel methods are presented, which include integrated structuring of the waveguide to control the refractive index properties and resultant optical fields, to external optical configurations that efficiently couple the fundamental guided mode to a free-space cavity mode. The chapter is concluded by reviewing exemplar planar-waveguide laser demonstrations, an overview of the current state of play, and future challenges and prospects.
