Upconversion Tm

3+

-doped fibre lasers have recently attracted much interest as compact and efficient blue light source. A CW room temperature upconversion laser at 480nm has been demonstrated. Since the high power laser with several hundreds milliwatts to several watts power at 980nm is commercially avai-lable and Yb

3+

ion has a large absorption cross-section around 980nm

the Tm

3+

Ho

3+

Er

3+

and Pr

3+

ions have successively been excited via the energy-transfer processes in different host by exploiting the Yb

3+

ions as sensitizers for the upconversion processes. On the other hand

the transition

3

F

4

→

3

H

6

of Tm

3+

at 1.8μm has applications in medicine and remote sensing

and consequently it has attracted a lot attention recently. In this paper

the visible and near infrared spectroscopic properties of Tm

3+

-Yb

3+

-codoped tellurite glasses and fibres under the excitation of a 980nm laser diode were investigated. Intense upconversion emissions at 480 and 800nm

and weak emission at 650nm

attributed to

1

G

4

→

3

H

6

3

H

4

→

3

H

6

and

1

G

4

→

3

F

4

transitions of Tm

3+

respectively

were recorded in Tm

3+

-Yb

3+

-codoped tellurite glasses at room temperature. The near infrared emissions at 1020 and 1810nm

which were attributed to transitions Yb

3+

:

2

F

5/2

→

2

F

7/2

and Tm

3+

:

3

F

4

→

3

H

6

respectively

were also observed. The emission characteristics dependence on Tm

3+

and Yb

3+

ions concentrations was also studied. In addition

intense upconversion emissions at 495 and 830nm

and weak emission at 650

and near infrared emissions at 1060

1470 and ~1910nm were recorded in Tm

3+

-Yb

3+

-codoped tellurite fibres using 980nm laser excitation. The luminescence mechanisms are discussed in detail for designing upconverted blue fibre laser

S-band fibre amplifier

and 1.9μm fibre laser for their potential application in clinical diagnosis and remote sensing.