Widely tunable short-infrared thulium and holmium doped fluorozirconate waveguide chip lasers

We report widely tunable (∼260 nm) Tm³⁺ and Ho³⁺ doped fluorozirconate (ZBLAN) glass waveguide extended cavity lasers with close to diffraction limited beam quality (M²∼1.3). The waveguides are based on ultrafast laser inscribed depressed claddings. A Ti:sapphire laser pumped Tm3+-doped chip laser continuously tunes from 1725 nm to 1975 nm, and a Tm³⁺-sensitized Tm³⁺:Ho³⁺ chip laser displays tuning across both ions evidenced by a red enhanced tuning range of 1810 to 2053 nm. We also demonstrate a compact 790 nm diode laser pumped Tm³⁺-doped chip laser which tunes from 1750 nm to 1998 nm at a 14% incident slope efficiency, and a beam quality of M²∼1.2 for a large mode-area waveguide with 70 μm core diameter.