Abstract

In this article, output power characteristics of cladding-pumped lasers based on bismuth-doped phospho- and germanosilicate core glass fibers were thoroughly studied and analyzed. The developed lasers are capable of providing the output power of several hundred milliwatts with the slope efficiency close to 1%. The output power saturation for the Bi-doped germanosilicate fiber laser and absence of the saturation regime for the Bi-doped phosphosilicate fiber one was found. This effect is explained by a relatively long relaxation time of bismuth active centers (BACs), namely a non-radiative transition from the higher-lying pump level to the upper laser (metastable) level in the corresponding energy levels diagram. The experimentally obtained data are in good agreement with the results of numerical simulation. In addition, it was investigated that the relaxation time of the BACs from the higher-lying level can have a significant impact on the laser efficiency and the achieved output power. The consequences caused by the saturation effect is possible to overcome with dual-wavelength pumping (combining cladding-pumping at 808-nm wavelength and core-pumping at a wavelength in the range of 1930 – 2040 nm), which provides both the BACs excitation and the stimulated relaxation of BACs from the excited (pump) state to the upper laser level. Using this approach the output power of the Bi-doped fiber laser was increased by almost two times.

Cladding-pumped bismuth-doped fiber laser

Sergei Firstov, Andrey Umnikov, Aleksandr Kharakhordin, Alexander Vakhrushev, Elena Firstova, Sergey Alyshev, Aleksandr Khegai, Konstantin Riumkin, Yan Ososkov, Aleksei Guryanov, and Mikhail Melkumov
Opt. Lett. 47(4) 778-781 (2022)

Cladding-pumped laser and amplifier for E- and S-bands based on multimode bismuth-doped graded-index fibers: toward “watt-level” output power

Alexander Vakhrushev, Andrey Umnikov, Alexander Dostovalov, Konstantin Riumkin, Sergey Alyshev, Elena Firstova, Aleksandr Khegai, Mikhail Melkumov, Sergey Babin, and Sergei Firstov
Opt. Lett. 49(7) 1828-1831 (2024)

Effect of pump wavelength and temperature on the spectral performance of BAC-Al in bismuth-doped aluminosilicate fibers

Qiancheng Zhao, Yanhua Luo, Yutang Dai, and Gang-Ding Peng
Opt. Lett. 44(3) 634-637 (2019)

Cladding pumped bismuth-doped fiber amplifiers operating in O-, E-, and S-telecom bands

Alexander Vakhrushev, Aleksandr Khegai, Sergey Alyshev, Konstantin Riumkin, Alexander Kharakhordin, Elena Firstova, Andrey Umnikov, Alexey Lobanov, Fedor Afanasiev, Aleksei Guryanov, Mikhail Melkumov, and Sergei Firstov
Opt. Lett. 48(6) 1339-1342 (2023)

Photostability of laser-active centers in bismuth-doped GeO₂–SiO₂ glass fibers under pumping at 1550 nm

Sergey Alyshev, Alexander Kharakhordin, Elena Firstova, Aleksandr Khegai, Mikhail Melkumov, Vladimir Khopin, Aleksey Lobanov, Alexey Guryanov, and Sergei Firstov
Opt. Express 27(22) 31542-31552 (2019)