Tm³⁺/Ho³⁺co-doped germanate glass and double-clad optical fiber for broadband emission and lasing above 2 µm

2.0 μm Ultra Broadband Emission from Tm3+/Ho3+ Co-Doped Gallium Tellurite Glasses for Broadband Light Sources and Tunable Fiber Lasers

“…The value is larger than that of Tm 3+ /Ho 3+ co-doped silicate-germanate glass (231.5 nm) [20] and silicate glass (189 nm) [24] and is slightly lower than that of Yb 3+ /Tm 3+ /Ho 3+ triply doped gallo-germanate glass (343 nm) [25]. Larger FWHM will provide a better opportunity to achieve broad amplified spontaneous emission (ASE) sources and tunable fiber lasers [4,7]. In addition, the dependence of Ho 3+ : 5 I7 lifetime on Ho2O3 concentration is presented in Figure 5.…”

“…In the past few decades, numerous studies have gone into achieving high-brightness broadband light sources and tunable fiber lasers operating at eye-safe 2.0 μm wavelength range because of broad applications in the fields of urology, gas sensing, remote atmospheric monitoring, and material processing, and their use as an efficient pumping source for obtaining mid-infrared supercontinuum [1][2][3][4][5][6]. It is well known that Tm 3+ : 3 F4→ 3 H6 and Ho 3+ : 5 I7→ 5 I8 radiative transitions are the most efficient and feasible ways to generate 2.0 μm emission when they are doped into an appropriate host glass.…”

“…It is well known that Tm 3+ : 3 F4→ 3 H6 and Ho 3+ : 5 I7→ 5 I8 radiative transitions are the most efficient and feasible ways to generate 2.0 μm emission when they are doped into an appropriate host glass. Moreover, both transitions work in the three-level quantum scheme and hence respective emission bands are relatively broad, which allows to obtain broadband emission from 1.7 to 2.1 μm [4,7]. Tm 3+ has an intense absorption band near 808 nm, which allows for the excitation of high-power and low-cost laser diode (LD).…”

Development of low‐loss lead‐germanate glass for mid‐infrared fiber optics: II. preform extrusion and fiber fabrication

“…Examples are narrow-linewidth (<7 kHz) single-frequency fiber laser 26 and all-fiber laser at 1.95 μm. 27,28 Furthermore, efficient laser generation of 2 μm has been realized in Ho 3+ doped germanate glasses and fibers, either singly doped 29,30 or co-doped with Tm 3+ , 31,32 Yb 3+ , 33,34 and/or Er 3+ as sensitizer 35 to transfer more efficiently the absorbed pump energy to the upper laser level of Ho 3+ ions. The Er 3+ :2.7 μm emission was also investigated for a range of germanate glasses 36,37 but no lasing was achieved to date.…”

Study on the dopant concentration ratio in thulium-holmium doped silica fibers for lasing at 2.1µm

“…Alternative to the in-band pumping scheme, co-doping of silica fibers with thulium and holmium can be considered [16,17]. In that case, the 79x nm pump can be utilized to excite thulium ions and promote the two-for-one cross-relaxation process, followed by a dominant donor-acceptor energy transfer mechanism from thulium 3 F 4 manifold to holmium 5 I 7 manifold [18,19] as shown in Fig.…”