Er3+/Yb3+ co-doped bismuthate glass and its large-mode-area double-cladding fiber for 1.53 μm laser

The role of tungsten oxide in Er3+-doped bismuth-germanate glasses for optical amplification in L-band

“…S3 of the Supplementary Material. However, the achieved values for the gain and gain bandwidth are similar to the ones reported in the literature 54 , 55 . Also, the FL theory shows that at least 30% of the Er 3+ ions should be at the excited state level to obtain a gain signal in the L-band in Fig.…”

Enhanced 1.5 μm emission from Yb3+/Er3+ codoped tungsten tellurite glasses for broadband near-infrared optical fiber amplifiers and tunable fiber lasers

“…7(a) presents the absorption and emission cross section as a function of wavelength in TWYE-1 glass. It is found that the maximum σ e of Er 3+ reaches 1.06 × 10 −20 cm 2 near 1.5 μm which is larger than those values reported in oxyfluorosilicate glass (4.88 × 10 −21 cm 2 ), 32 lead phosphate glass (4.9 × 10 −21 cm 2 ), 29 bismuthate glass (8.2 × 10 −21 cm 2 ) 33 and gallogermanate glass (7.6 × 10 −21 cm 2 ), 2 indicating that high gain coefficient and low pump threshold can be excepted in the present glass. 34 Large emission cross section of Er 3+ in TWYE-1 glass is due to high refractive index.…”

“…Moreover, positive gain coefficient is obtained when p is higher than 0.2, indicating a lower pump threshold. It is worth noting that the maximum gain coefficient of TWYE-1 glass is 4.07 cm −1 at 1534 nm, which is larger than those values reported in borosilicate glass (1.01 cm −1 ), 22 phosphate glasses (1.02 cm −1 ), 36 bismuthate glass (3.51 cm −1 ) 33 and niobium germanate glass (0.28 cm −1 ). 30 …”

“…Fig. 7 33 and niobium germanate glass (0.28 cm À1 ). 30 Gain bandwidth is a key parameter for optical ber ampli-ers and is usually dened as the product of FWHM and cm 3 ).…”

“…The emission cross section (s e ) can be estimated by the following McCumber formula: 31 s e ðlÞ ¼ s a ðlÞwhere s a is absorption cross section, Z l and Z u represent the partition function of the lower and upper state for 4 I 13/2 / 4 I 15/2 transition, respectively, k B is the Boltzmann constant, T is the temperature and E ZL is the zero-line energy, dened as the energy difference between the lowest stark of the upper and lower manifolds. The absorption cross section can be estimated by the Beer-Lambert equation:17 It is found that the maximum s e of Er 3+ reaches 1.06 Â 10 À20 cm 2 near 1.5 mm which is larger than those values reported in oxyuorosilicate glass (4.88 Â 10 À21 cm 2 ), 32 lead phosphate glass (4.9 Â 10 À21 cm 2 ),29 bismuthate glass (8.2 Â 10 À21 cm 2 )33 and gallogermanate glass (7.6 Â 10 À21 cm 2 ), 2 indicating that high gain coefficient and low pump threshold can be excepted in the present glass 34. Large emission cross section of Er 3+ in TWYE-1 glass is due to high refractive index.…”