Enhanced long-wavelength emission and 2109 nm lasing in Tm 3+ /Ho 3+ co-doped germanate-core/silicate-cladding glass fiber
Year: 2025
Type: article
Abstract: Fiber lasers emitting beyond 2.1 μm remain attractive owing to their superior performance in molecular “fingerprint” gas sensing, supercontinuum generation, and advanced bioimaging applications. The Ho 3+ : 5 I 7 → 5 I 8 transition offers a larger emission cross-section and a longer metastable lifetime than Tm 3+ at 2.1 μm. However, the scarcity of commercial pump sources has hindered the widespread adoption of Ho 3+ -doped fiber lasers. Tm 3+ /Ho 3+ co-doping has emerged as an effective strategy to address this limitation. In this work, a Tm 3+ /Ho 3+ co-doped BaO-Sb 2 O 3 -GeO 2 (BSG) germanate glass exhibiting low phonon energy (∼810 cm -1 ) and high crystallization resistance (Δ T = 250°C) was designed. To optimize long-wavelength emission from Ho 3+ , both forward and reverse energy transfer processes were systematically investigated using spectroscopic measurements and molecular dynamics simulations. Employing a melt-in-tube technique, we fabricated a germanate-core/silicate-cladding glass fiber that combines the extended fluorescence lifetime of Ho 3+ : 5 I 7 → 5 I 8 (4.60 ms) with the mechanical robustness of a silicate cladding. Compared with previously reported Tm 3+ /Ho 3+ co-doped fibers, the custom-designed fiber exhibits an amplified spontaneous emission peak dominated by Ho 3+ near 2.1 μm. Laser output at 2109 nm was achieved in a 2 cm fiber, approximately 1/50 the length of a typical silica fiber, underscoring its high potential as a gain medium for integrated fiber devices operating beyond 2.1 μm.
Source: Optics Express
DOI: 10.1364/oe.577646
Language: English
Subfield: Ceramics and Composites
Field: Materials Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,270
Awards: G5009670670, G8640374870
OpenAlex ID: W4415841308