1.5mm emission from the first excited state to the ground state of Er

3+

is very important for the applications in integrated optics and lasers.And we know that for a given transition of trivalent rare earth ions its properties mainly depends on the surroundings

say

host where the rare earth ions are inside.At this point

in order to find a better host material to incorporate the Er

3+

a lot of kinds of materials

such as sulfide

chloride

fluoride

oxide glasses

and some kinds of crystals have been studied.Finally

amongst these materials the phosphate glass is thought to be a promising candidate for practical application.But there are problems still left to be solved

like chemical stability

lower transition temperature

and so on.In the present paper

a special host glass composition has been designed.Three samples with different Er concentration have been produced.Absorption spectra for these samples have been measured

the calculation results of absorption cross sections for the samples indicated that for a certain transition they are analogous.J-O parameters have been obtained to be 4.4(Ω

2

)

1.3(Ω

4

) and 1.1×10-2cm

2

(Ω

6

).Using the J-O parameters the oscillator strengths

radiative transition probabilities for other transitions and radiative transition lifetimes for some levels have been derived.Emission cross sections for the transition

4

I

13/2

→

4

I

15/2

have been obtained by using absorption spectra data or emission spectra data.A comparison between the emission cross sections derived from different approaches shows that week reabsorption is existent even in the sample containing 5% of Er

3+

this fact implies that Er

3+

doped this kind of material is suitable for the application in integrated optics.Fluorescence decay for the transition

4

I

13/2

→

4

I

15/2

room temperature has been measured for the samples with different Er

3+

concentration.It is shown that for all the samples

its fluorescence decay lines obey the single exponential function.Through some calculations it could be concluded that the interaction type between Er

3+

ions is of electric dipole

and the quantum efficiency for the transition

4

I

13/2

→

4

I

15/2

in our phosphate glass with lower Er

3+

concentration is close to 100%.From the facts above it is expected that our phosphate glass would be an advanced material for the practical applications in integrated optics and lasers.