Dielectric Solid-State Planar Waveguide Lasers: A Review

This review takes a look at the historical development of the dielectric planar waveguide laser leading to key state-of-the-art technologies that fall within this broad subject area. Discussed herein are many of the advantages offered by the waveguide geometry such as high optical gain, and thus, low threshold-power requirements, suitability for quasi-three-level laser transitions, integration with functional devices on single substrates, guided spatial-mode control, and its considerable immunity to thermal effects and external environmental conditions. A detailed snapshot is made of many active host media for which there has been reported laser action in the planar waveguide geometry, covering many of the major rare-earth-ion transitions. Several fabrication techniques are highlighted and appraised for their applicability to different host media, touching on their benefits and drawbacks. Challenges and future prospects for these lasers are considered.