Abstract

Heavy-metal fluoride glass is well known for its high infrared transparency, especially in its most common composition ZrF₄-BaF₂-LaF₃-AlF₃-NaF (ZBLAN), which makes it an attractive host for mid-infrared emitting rare-earth ions. The mid-infrared wavelength region is of particular interest for many applications like molecular spectroscopy, process monitoring and infrared countermeasures, which demand a robust, simple and cheap laser source. We recently demonstrated a Tm³⁺:ZBLAN waveguide laser emitting at 1.9 µm with a slope efficiency approaching 40% [1]. The device is based on novel laser-written depressed cladding waveguides with butt-coupled bulk mirrors. However to obtain a highly integrated and robust laser system a different approach to providing the resonator feedback must be applied. A significant innovation would be the integration of Bragg-gratings into the waveguide in the form of distributed feedback (DFB) or distributed Bragg reflector (DBR) structures, thereby resulting in a monolithic device with narrow line width output [2].

© 2011 Optical Society of America