Er 3+-doped GeGaSbS glasses for mid-IR fibre laser application: Synthesis and rare earth spectroscopy
With an infrared transparency extended to 10 μm, low multiphonon relaxation rates and suitable rare earth solubility, sulphide glasses in the Ge–Ga–Sb–S system allow radiative emission from rare earth ions in the mid-IR range. The Er 3+ ion, widely studied in glass fibres for optical amplification a...
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Published in | Optical materials Vol. 31; no. 1; pp. 39 - 46 |
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Main Authors | , , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
Elsevier B.V
2008
|
Subjects | |
Online Access | Get full text |
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Summary: | With an infrared transparency extended to 10
μm, low multiphonon relaxation rates and suitable rare earth solubility, sulphide glasses in the Ge–Ga–Sb–S system allow radiative emission from rare earth ions in the mid-IR range. The Er
3+ ion, widely studied in glass fibres for optical amplification at 1.5
μm, presents an interesting transition for mid-IR applications around 4.5
μm (
4I
9/2
→
4I
11/2). Thus, the aim of this work is to evaluate the Er
3+-doped Ge
20Ga
5Sb
10S
65 glass as a potential fibre laser source operating in the 3–5
μm mid-IR spectral region. For that purpose, absorption and emission spectra were recorded from visible to mid-IR and the radiative lifetimes of the involved excited levels (
4I
9/2,
4I
11/2 and
4I
13/2) were determined. Experimental results were compared with those obtained from a Judd–Ofelt analysis based on the absorption cross-sections of all observable transitions. The
4I
9/2 radiative quantum efficiency was estimated to be 64% and the emission cross-section at 4.6
μm was found equal to 2.85
×
10
−21
cm
2. Core only and core/clad Er
3+-doped Ge
20Ga
5Sb
10S
65 glass fibres were successfully drawn with minimum optical losses of about 1.5 and 10
dB/m at 5.2 and 3.5
μm, respectively. Fluorescence signals in the mid-IR (at 2.7 and 4.6
μm) were clearly observed with both fibres. |
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ISSN: | 0925-3467 1873-1252 |
DOI: | 10.1016/j.optmat.2008.01.005 |