Enhanced 1.53
l
m radiative transition in Er
3+
/Ce
3+
co-doped tellurite
glass modified by B
2
O
3
oxide
Fengjing Yang, Bo Huang, Libo Wu, Yaxun Zhou
⇑
, Fen Chen, Gaobo Yang, Jun Li
College of Information Science and Engineering, Ningbo University, Zhejiang 315211, China
article info
Article history:
Received 28 May 2015
Received in revised form 27 June 2015
Accepted 6 July 2015
Available online 15 July 2015
Keywords:
Tellurite glass
Er
3+
/Ce
3+
co-doping
B
2
O
3
modification
1.53
l
m band emission
Energy transfer
abstract
Er
3+
/Ce
3+
co-doped and B
2
O
3
modified tellurite glasses with initial composition of TeO
2
–GeO
2
–Li
2
O–
Nb
2
O
5
were prepared using melt-quenching technique for potential applications in Er
3+
-doped fiber
amplifiers (EDFAs) and lasers. The absorption spectra, fluorescence spectra, up-conversion spectra,
Raman spectra and differential scanning calorimeter (DSC) curves of glass samples were measured to
evaluate the effect of B
2
O
3
modification on the 1.53
l
m band spectroscopic properties of Er
3+
, structural
nature and thermal stability of glass hosts. It was shown that the introduction of an appropriate amount
of B
2
O
3
oxide can further improve the 1.53
l
m band fluorescence emission through an enhanced
phonon-assisted energy transfer (ET) from Er
3+
to Ce
3+
ions under the excitation of 980 nm, and the quan-
titative studies were carried out to elucidate the ET mechanism via calculating the microscopic parame-
ters and phonon contribution ratios. Meanwhile, the thermal stability of glass hosts increases slightly
with the introduction of B
2
O
3
oxide. Furthermore, the 1.53
l
m band optical signal amplification was sim-
ulated based on the rare-earth ion rate and light power propagation equations. An increment in signal
gain by about 1.4 dB at 1532 nm was observed in the Er
3+
/Ce
3+
co-doped tellurite glass fiber containing
6 mol% amount of B
2
O
3
oxide, and the maximum signal gain reaches to 31 dB on a 50 cm fiber pumped at
980 nm with power 200 mW. The present results indicate that the prepared Er
3+
/Ce
3+
co-doped tellurite
glass modified by an appropriate amount of B
2
O
3
oxide has good prospect as a gain medium applied for
1.53
l
m band EDFAs and lasers.
Ó 2015 Elsevier B.V. All rights reserved.
1. Introduction
With the rapid growth of multimedia communication data in
recent years, the demand of much faster speed and higher capacity
of wavelength-division-multiplexing (WDM) optical transmission
system has become more and more urgent [1,2]. As a key device
in this system, conventional silica-based Er
3+
-doped fiber amplifier
(EDFA) with the narrow gain spectrum (40 nm) [3] has now been
unable to meet this growing demand. Therefore, it is important to
look for new optical amplifiers with a wide and flat gain spectrum
to be used in the WDM transmission system. It has been reported
that the EDFA made from tellurite-based glass exhibited a flat
amplification of 20 dB across 80 nm gain spectrum in the wave-
length range of 1530–1610 nm [4], which is ideal for the broad
optical communication application. As a host material, tellurite
glass has also caught a great attention owing to its numerous
advantages such as easier preparation process, better physical sta-
bility and chemical durability, larger transparency window (0.35–
5
l
m), higher rare-earth (RE) ion solubility and higher refractive
index (2.0) [5–7].
Compared with other oxide glasses such as germanate
(900 cm
1
) [8], silicate (1100 cm
1
) [9] and phosphate
(1300 cm
1
) [10] glasses, the phonon energy of tellurite glass
(750 cm
1
) [11] is lower, which results in strong visible
up-conversion emission due to the excited state absorption (ESA)
of Er
3+
ions at the
4
I
11/2
level under the excitation of 980 nm [12],
and in turn decreases the 1.53
l
m band fluorescence emission. In
order to improve the 1.53
l
m band fluorescence intensity, it is nec-
essary to take some measures to suppress the visible
up-conversion emission by rapidly de-exciting the Er
3+
ions popu-
lated at the
4
I
11/2
level, which can be realized through accelerating
the non-radiative relaxation process of Er
3+
ions from the
4
I
11/2
to
4
I
13/2
levels [13]. Yang et al. [14] have demonstrated that
Er
3+
/Ce
3+
co-doping scheme was an effective measure to improve
the feeding rate of
4
I
11/2
?
4
I
13/2
transition with the help of energy
transfer (ET) process: Er
3+
:
4
I
11/2
+Ce
3+
:
2
F
5/2
? Er
3+
:
4
I
13/2
+
Ce
3+
:
2
F
7/2
. However, there exists an energy difference
(
D
E 1400 cm
1
) between the Er
3+
:
4
I
11/2
?
4
I
13/2
transition and
the Ce
3+
:
2
F
5/2
?
2
F
7/2
transition, since the energy gap between
http://dx.doi.org/10.1016/j.optmat.2015.07.008
0925-3467/Ó 2015 Elsevier B.V. All rights reserved.
⇑
Corresponding author.
E-mail address: zhouyaxun@nbu.edu.cn (Y. Zhou).
Optical Materials 47 (2015) 149–156
Contents lists available at ScienceDirect
Optical Materials
journal homepage: www.elsevier.com/locate/optmat
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