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6LS-I-3
LASER SYSTEMS AND MATERIALS
Ultrafast composite fiber-based lasers and amplifiers for the 1.53-1.59 um spectral region
A.D. Zverev1, V.A. Kamynin1, B.I. Denker1, S.E. Sverchkov1, V.V. Vel'miskin2, I.S. Panyaev3, P.A. Itrin3, D.A. Korobko3, I.O. Zolotovskii3, V.B. Tsvetkov1
1 - Prokhorov General Physics Institute of Russian Academy of Sciences, Moscow, Russia 2 - Prokhorov General Physics Institute of the Russian Academy of Sciences, Dianov Fiber Optics Research Center, Moscow, Russia 3 - S.P. Kapitsa Scientific Technological Research Institute, Ulyanovsk State University, Ulyanovsk, Russia
Main author email address: kamyninva@gmail.com
Modern photonics devices production requires new robust and technological basic elements. For digital-to-analog-conversion it is laser sources withstable high repetition rate ultrashort pulses (USPs) and for signal transmission it is fiber amplifiers operating in the spectral range of 1.5 ^m. Both are in great demand of active media with high gain per unit length coefficient. Thus, the development of such active media is an actual problem. One of the ways to achieve high gain per unit length coefficient is to increase rare-earth elements concentration in fiber core. And it was successfully demonstrated in phosphate fibers: 3 dB/cm gain coefficient [1], and lead realization of tens of GHz repetition rates sources [2]. Despite impressive on-the-table results presented, active fibers have a few serious lacks: degradation in atmospheric moisture and complicated connection to standard optical fibers. In early 2010s FORC RAS and GPI RAS developed composite fiber with a heavily erbium-doped core (3 wt.%) and a silicon cladding that prevents fiber degradation and provides the ability to splice with standard optical components [3]. The fiber combined advantages as phosphate fibers so standard ones.
Now a family of composite Er-, and Er-Yb codoped active fibers were developed. Based on one mentioned media, a passively mode-locked ring laser based on a multicomponent fiber with silica cladding and a 3 wt. % Er-doped phosphate core was realized [4]. The active fiber length was about 19 cm. The laser emitted 570 fs pulses at a repetition rate of 23.9 MHz with an average output power of 1.4 mW. Further active fiber shortening and changing cavity topology to a linear one allowed us to achieve a composite Er-doped fiber laser passively mode-locked by aerosol-synthesized SWCNT film. A stable USPs with a repetition rate of 150 MHz and duration of 973 fs was demonstrated [5].
In the case of USPs amplification, composite active fibers can be promising due to high gain per unit length that lead to decreasing pulses distortion during amplification. It was demonstrated that ultrashort pulses could be amplified in a short composite fiber (20 cm) with a high concentration of Er ions (3 wt.%). Today, we have compared the amplification of ultrashort pulses in amplifiers based on a 31 cm of composite fiberdoped with an Er/Yb complex and standard Er-doped fiber. Analysis of the FROG traces shows that the distortion of the pulse shape in a standard fiber occurs at lower signal gain values.
We believe that composite fiber with high mechanical stability and low air moisture sensitivity supporting splicing with standard silica fibers allows the implementation of a wide range of all-fiber devices and makes it possible to create USPs sources and amplifiers operating at repetition rates between 100 MHz and 10 GHz.
The composite fibers were fabricated within the RFBR project No. 20-02-00425 "Composite optical fibers activated by rare-earth ions".
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[2]R. Thapa,, D.Nguyen, J.Zong, A.Chavez-Pirson, All-fiber fundamentally mode-locked 12 GHz laser oscillator based on an Er/ Yb-doped phosphate glass fiber, Optics Letters, vol. 39(6), 1418-1421.(2014).
[3] B.I. Denker, B.I. Galagan, V.A. Kamynin, A.S. Kurkov1, Ya.E. Sadovnikova, S. L. Semenov, S. E. Sverchkov, V.V. Velmiskin, E. M. Dianov, "Composite laser fiber with Yb, Er co-doped phosphate glass core and silica cladding, Laser Phys Lett,vol. 10(5), 055109 (2013).
[4] B. I. Denker, B. I. Galagan,.V. A.Kamynin, A. APonosova, S. ESverchkov, S. LSemjonov, V. B. Tsvetkov, Femtosecond laser based on a multicomponent fiber with a 3 wt.% Er-doped phosphate core and silica cladding. Laser Physics Letters, vol. 16(8), 085103,(2019).
[5] A.D. Zverev, V.A. Kamynin, S.A. Filatova, V.G. Voronin, V.B. Tsvetkov, B.I. Galagan, S.E. Sverchkov, B.I. Denker, V.V. Vel'miskin, Y.G. Gladush, E.M. Khabushev, D.V. Krasnikov, A.G. Nasibulin,Passively mode-locked composite erbium fiber laser with a pulse repetition rate of 150 MHz,Optik,vol. 249, (2022).
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