According to Judd-Ofelt theory the intensity parameters of Tm

3+

in crystal TmP

5

O

14

were measured.Their values are Ω

2

=1.50×10

-20

cm

2

Q

4

=1.5×10

-20

cm

2

and Ω

6

=0.916×10

-20

cm

2

respectively.The calculated oscillator strengths Pcal.agree with the experimental values Paxp.quite well

the root mean square deviation(rms)is 2.60×10

-7

.With these Ω

λ

values

the oscillator strengths

spontaneous radiative transition rates

radiative lifetimes and branching ratios between the excited J manifolds were calculated.The spectral parameters obtained were compared with

those of crytals YAlOs:Tm

3+

YAG:Tm

3+

Y

2

O

3

:Tm

3+

and glasses doped with Tm

3+

.The summation of intensity parameters(∑τλ=τz +τ

4

+τ

6

)of Tm

3+

in crystal TmP

5

O

14

are lower than those of phosphate glass as well as other glasses(borate

germanate and tellurate).∑τλ is a parameter

we found that it is proportional to the oscillator strength P and may be expressed by following equation:P=α∑τλ+b where a and b are two constants obtained from experiments.