Ultra-broadband emission in Er³⁺/Tm³⁺/Ho³⁺ triply-doped germanate glass and double-clad optical fiber

Abstract

In this paper 1400 nm–2200 nm broadband emission under 808 nm and 976 nm laser diodes excitation in germanate glasses co-doped with (0.35–0.7) Er2O3/(0.35–0.7) Tm2O3/(0–0.15) Ho2O3 (mol%) are presented. Flattened luminescence profiles were achieved as a result of RE content optimization in glasses co-doped with 0.35Er2O3/0.7Tm2O3/0.15Ho2O3, (λexc = 808 nm) and 0.7Er2O3/0.35Tm2O3/0.07Ho2O3, (λexc= 976 nm). The second, glass characterized by the widest emission range, has been used for the fabrication of double-clad optical fiber with 15 µm/250 µm (core/outer cladding) diameters. The optimization of broadband spectrum in glass and optical fiber was performed as the result of the superposition of 1550 nm (Er3+: 4I13/2 → 4I15/2), 1800 nm (Tm3+: 3F4 → 3H6), and 2000 nm (Ho3+:5I7 → 5I8) emission bands. The influence of optical fiber length and pump wavelength on near-infrared amplified spontaneous emission (ASE) features have been determined. As a result, the broadest bandwidth of ASE (415 nm - 3 dB and 731 nm – 10 dB) was obtained in 5 m length optical fiber under 808 nm pumping. It is significantly broader than in silica and tellurite fibers, which showed the advantage of RE triply-doped germanate optical fiber.

Advances in laser‐based manufacturing techniques for specialty optical fiber

“…Furthermore, co‐doping with rare‐earth (RE) ions as well as multi‐layered cladding is common in active optical devices 11 . Countless doping schemes and layouts containing, among others, Er, Yb, Nd, Ho, Tm 39–44 in various applications include, for example, telecom erbium‐doped fiber amplifiers and lasers 45,46 or high‐power ytterbium‐doped fiber lasers widely used in laser‐based machining 47 …”

Broadband Profiled Eye-Safe Emission of LMA Silica Fiber Doped with Tm3+/Ho3+ Ions

“…Germanium and aluminum are typically used to increase the refractive index, while lanthanide compounds are used for luminescence generation [20,21]. For the considered range of radiation (1.4-2.2 µm), Er 3+ , Tm 3+ , and Ho 3+ ions can be used [20,[22][23][24][25][26][27]. One of the most commonly used technologies for the production of silica optical fibers is the modified chemical vapor phase deposition (MCVD) method.…”