Abstract

Lanthanum fluoride, has a number of properties that make it an attractive host material for rare-earth (RE) lasing dopants. It has a very low maximum phonon energy (~380 cm^–1) and a large transparency window, leading to the possibility of accessing RE transitions that normally suffer from efficient non-radiative decay in other hosts. Combination with a waveguide geometry, could lead to efficient, low threshold, integrated devices that operate over a wide range of wavelengths. Recently we demonstrated the first laser action in a neodymium-doped lanthanum fluoride planar waveguide [1]. This was the first laser action achieved in a RE-doped, fluoride thin-film fabricated by molecular beam epitaxy (MBE). The fabrication technique allows very accurate control of the thickness and doping level of the thin-film, and potentially also over the doping and refractive index profiles. Here we report on investigations into producing slab-loaded channel waveguide lasers based on these MBE planar thin-films, to further lower the laser threshold and give a more circular spatial output.

© 2000 IEEE