1Yb 2 O 3 /0.1Tm 2 O 3 . Based on the analysis of the luminescence decay time from the
Yb
3+ :
2 F 5/2 level, the efficiency of the donor-acceptor energy transfer was calculated.
The lifetime of this level reduces from 781 µs (1Yb 2 O 3 ) to 71 µs in the presence of
Tm
3+ ions (1Yb 2 O 3 /0.75Tm 2 O 3 ), which implies the maximum efficiency of the
Yb
3+
! Tm
3+ energy transfer at 90%. In turn, the highest value of luminescence
intensity in the visible range was obtained in glass co-doped with 1Yb 2 O 3 /
0.1Tm 2 O 3 . Therefore, this glass was used as the core of the fabricated double-clad
optical fiber. This optical fiber was drawn using modified “rod-in-tube” method. Its
basic parameters are as follows: outer diameter = 340 µm, core diameter = 10 µm,
NA cladding = 0.58, NA core = 0.2. Attenuation of amplified spontaneous emission
(ASE) signal at the wavelength of 481 nm was 3.29 dB/m.
Another scientific problem, which has not been analyzed in the literature yet,
was a comparison of the luminescence spectra of core glass and fabricated optical
fiber, and next the analysis of mechanisms that have the impact on these differences.
The analysis was conducted on the basis of two fabricated optical fibers doped with
Yb 2 O 3 /Tm 2 O 3 and Yb 2 O 3 /Ho 2 O 3 . According to the analysis of luminescent
properties of the optical fiber of the 1–2.5 m length under classical pumping of one
end type, the shift of the maximum of the emission has been observed in the range
of blue color (481 nm) of 3 nm toward longer wavelengths (Fig. 14.21). This effect
is the result of the optical trapping resulting from the Tm
3+ :
3 H 6 !
1 G 4 transition
occurring in the shortwave part of the ASE signal propagating in the core. In the
above process, radiation emitted by ions located at the beginning of optical fiber is
partially reabsorbed by ions of active admixture during the propagation along the
optical fiber.
Fig. 14.21 Comparison of the emission spectra of core glass and double-clad optical fiber
co-doped with 1Yb 2 O 3 /0.1Tm 2 O 3 mol%, intensity I 481mn /I 653nm ratio as a function of the length of
the fiber and the photograph of the optical fiber (inset)
14 The Luminescent Properties of Photonic Glasses …
445
Yb
3+ :
2 F 5/2 level, the efficiency of the donor-acceptor energy transfer was calculated.
The lifetime of this level reduces from 781 µs (1Yb 2 O 3 ) to 71 µs in the presence of
Tm
3+ ions (1Yb 2 O 3 /0.75Tm 2 O 3 ), which implies the maximum efficiency of the
Yb
3+
! Tm
3+ energy transfer at 90%. In turn, the highest value of luminescence
intensity in the visible range was obtained in glass co-doped with 1Yb 2 O 3 /
0.1Tm 2 O 3 . Therefore, this glass was used as the core of the fabricated double-clad
optical fiber. This optical fiber was drawn using modified “rod-in-tube” method. Its
basic parameters are as follows: outer diameter = 340 µm, core diameter = 10 µm,
NA cladding = 0.58, NA core = 0.2. Attenuation of amplified spontaneous emission
(ASE) signal at the wavelength of 481 nm was 3.29 dB/m.
Another scientific problem, which has not been analyzed in the literature yet,
was a comparison of the luminescence spectra of core glass and fabricated optical
fiber, and next the analysis of mechanisms that have the impact on these differences.
The analysis was conducted on the basis of two fabricated optical fibers doped with
Yb 2 O 3 /Tm 2 O 3 and Yb 2 O 3 /Ho 2 O 3 . According to the analysis of luminescent
properties of the optical fiber of the 1–2.5 m length under classical pumping of one
end type, the shift of the maximum of the emission has been observed in the range
of blue color (481 nm) of 3 nm toward longer wavelengths (Fig. 14.21). This effect
is the result of the optical trapping resulting from the Tm
3+ :
3 H 6 !
1 G 4 transition
occurring in the shortwave part of the ASE signal propagating in the core. In the
above process, radiation emitted by ions located at the beginning of optical fiber is
partially reabsorbed by ions of active admixture during the propagation along the
optical fiber.
Fig. 14.21 Comparison of the emission spectra of core glass and double-clad optical fiber
co-doped with 1Yb 2 O 3 /0.1Tm 2 O 3 mol%, intensity I 481mn /I 653nm ratio as a function of the length of
the fiber and the photograph of the optical fiber (inset)
14 The Luminescent Properties of Photonic Glasses …
445