Abstract

Lanthanide-doped fiber lasers are sought after for many applications, as they can generate high-brightness signals through some of the most compact, rugged, and reliable laser systems available. Although high power fiber lasers have been mostly reported between 1 and 3 µm, the recent advent of GaN laser diodes has provided a low-cost solution to efficiently pump lanthanide-doped fibers for visible laser emission. To date, watt-level operation of these lasers has been reported [1, 2], but only for active fibers based on fluoride glass, which is known for its constraining thermal and mechanical properties. While the use of such a host is needed for mid-infrared lasers due to its low phonon energy, it is not necessarily the case for visible laser emission. Indeed, for some rare-earth ions like Sm³⁺ and Dy³⁺, the large energy gap between the upper energy level responsible for visible emission (in the case of Dy³⁺, ⁴F_9/2) and the energy level directly below (in the case of Dy³⁺, ⁶F_5/2) allows a high phonon energy medium such as silica to be a suitable host for laser emission [3]. While visible silica fiber lasers show a lot of promise due to their excellent thermal and mechanical properties, very few demonstrations of such lasers have been made. Thus far, the record output power is set to 18 mW [4]. In this work, we present a monolithic Dy³⁺-doped aluminosilicate fiber laser yielding a maximum output power of 147 mW, which is eight times more than the previous record.

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