Liquid-cooled 24 W mid-infrared Er:ZBLAN fiber laser

Abstract

A 24 W liquid-cooled CW 3 microm fiber laser with a multimode-core Er-doped ZBLAN fiber has been developed. The output power of 24 W and an optical-to-optical efficiency of 14.5% (with respect to incident pump power) were obtained with 975 nm diode pumping. Efficient cooling was implemented by a combination of fluid cooling over the entire length of the fiber and conductive cooling at both end faces of the fiber. Consequently, stable high-power operation was demonstrated. To our knowledge, this is the highest output power obtained by a 3 microm fiber laser. Furthermore, the high power can be further scaled up, since the output power in the present work is limited only by the available pump power.

Er3+-doped fluoro-tellurite glass: A new choice for 2.7μm lasers

“…As the host for mid-infrared solid-state lasers, Er 3+ -doped ZrF 4 -BaF 2 -LaF 3 -AlF 3 -NaF fluoride glass (ZBLAN) has been broadly investigated since the early 1990s [5]. To date 10-W-level output power without liquid cooled [6] and 24-W-level output power with liquid cooled [7] have been obtained in Er 3+ -doped ZBLAN fiber lasers. However, the poor thermal properties compared with those of oxide-based glasses strongly limited their real application in mid-infrared (MIF) lasers [8][9][10].…”

Energy level decay and excited state absorption processes in erbium-doped tellurite glass

“…To date, high power fibre lasers emitting on this transition have been achieved only in fluorozirconate based fibres. [5][6][7][8] Due to the hygroscopic nature of fluoride based glasses, it is difficult to avoid the degradation of the glass that occurs when exposed to moisture in the atmosphere. Tellurite glasses show potential as an alternative oxide based host material due to their relatively low maximum phonon energies ($690 cm À1 for the Er 3þ -doped tellurite (TZNL) glass composition used here) when compared to other oxide glasses.…”

High-power diode-pumped fiber laser operating at 3 μm

“…Traditionally, research into fiber lasers using fluoride glasses operating in the far shortwave region of the spectrum has been driven by requirements in medicine and materials processing; however, as demands develop from mid-IR photonics, pushing the emission wavelength of fiber lasers further into the mid-IR is desirable. To date, the rare earth ions erbium [2], holmium [3], and dysprosium [4] have created the highest output power and efficiency in the far shortwave IR region with the former two ions also generating low power emission in the near mid-IR region albeit at low efficiencies [5][6][7].…”