2μm Fiber Laser Research Articles

Tm3+/Ho3+ co-doped tellurate glass with high emission cross section for 2μm fiber lasers

A modified melt quenching technique was used to prepare new Tm3+/Ho3+ co-doped TeO2-Ta2O5-La2O3 (TTL) glass with high emission cross section. By standing the traditional tube furnace sideways, the melt quenching method is optimized to produce tellurate glass efficiently and simply. The performance of the glass system is studied in detail, and the possibility of this glass system as a 2.0 μm fiber laser material is obtained. The glass system was obtained by test analysis to have large refractive index (nd>2.01) and density (>5.28 g/cm3), excellent mechanical properties (>4.5Gpa). TTL5 glass was obtained with excellent glass transition temperature (Tg>439 °C) and good resistance to crystallization based on thermodynamic analysis(ΔT>170 °C). In addition, the bonding structure was studied and maximum phonon energy of TTL5 glasses was determined to be ∼669 cm−1 by Raman. The SEM micrographs show well the surface micromorphology of TTL3 and TTL5, and EDAX verifies that the results of elemental analysis of this system of glasses are reliable. Fluorescence spectroscopy demonstrated a TTL5 series of samples with 2.0 μm strong emission. Finally, the absorption emission cross-sections of Ho3+ were calculated to be as high as7.92×10−21 (at 1963 nm) and 12.301×10−21 (at 2061 nm), respectively, with a maximum gain factor of 2.75 cm−1. The results show that this new TTL series glass has high thermal stability, low phonon energy, and efficient 2.0 µm fluorescence, extending the tellurite glass system and being a good candidate for obtaining efficient 2.0 µm emission.

Novel Tm3+/Ho3+ Co-Doped Tellurate Glass with High Emission Cross Section for 2μm Fiber Lasers

Novel Tm3+/Ho3+ Co-Doped Tellurate Glass with High Emission Cross Section for 2μm Fiber Lasers

A 70 W thulium-doped all-fiber laser operating at 1940 nm

An all-fiber thulium-doped fiber laser operating at a wavelength of 1940 nm is reported. A maximum output continuous-wave power of 70.7 W with a slope efficiency of 59%, determined with respect to the absorbed pump power, was demonstrated. The laser delivered almost a single-mode beam with a beam quality factor of < 1.3.Full Text: PDF ReferencesM. N. Zervas and C. A. Codemard, "High Power Fiber Lasers: A Review", IEEE J. Sel. Top. Quantum Electron. 20, 0904123 (2014). CrossRef D. J. Richardson, J. Nilsson, and W. A. Clarkson. "High power fiber lasers: current status and future perspectives [Invited]", J. Opt. Soc. Am. B 27, B63 (2010). CrossRef J. Swiderski, A. Zajac, and M. Skorczakowski, "Pulsed ytterbium-doped large mode area double-clad fiber amplifier in MOFPA configuration", Opto-Electron. Rev. 15, 98 (2007). CrossRef M. Eckerle et al. "High-average-power actively-modelocked Tm3+ fiber lasers", Proc. SPIE 8237, 823740 (2012). CrossRef J. Swiderski, D. Dorosz, M. Skorczakowski, and W. Pichola, "Ytterbium-doped fiber amplifier with tunable repetition rate and pulse duration", Laser Phys. 20, 1738 (2010). CrossRef P. Grzes and J. Swiderski, "Gain-Switched 2-μm Fiber Laser System Providing Kilowatt Peak-Power Mode-Locked Resembling Pulses and Its Application to Supercontinuum Generation in Fluoride Fibers", IEEE Phot. J. 10, 1 (2018). CrossRef S. Liang et al. "Transmission of wireless signals using space division multiplexing in few mode fibers", Opt. Express 26, 6490 (2018). CrossRef J. Swiderski, M. Michalska, and P. Grzes, "Broadband and top-flat mid-infrared supercontinuum generation with 3.52 W time-averaged power in a ZBLAN fiber directly pumped by a 2-µm mode-locked fiber laser and amplifier", Appl. Phys. B 124, 152 (2018). CrossRef F. Zhao et al. "Electromagnetically induced polarization grating", Sci. Rep. 8, 16369 (2018). CrossRef J. Sotor et al. "Ultrafast thulium-doped fiber laser mode locked with black phosphorus", Opt. Lett. 40, 3885 (2015). CrossRef M. Olivier et al. "Femtosecond fiber Mamyshev oscillator at 1550 nm", Opt. Lett. 44, 851 (2019). CrossRef J. Swiderski and M. Michalska, "Over three-octave spanning supercontinuum generated in a fluoride fiber pumped by Er & Er:Yb-doped and Tm-doped fiber amplifiers", Opt. Laser Technol. 52, 75 (2013). CrossRef C.Yao et al. "High-power mid-infrared supercontinuum laser source using fluorotellurite fiber", Optica 5, 1264 (2018). CrossRef J. Swiderski and M. Maciejewska, "Watt-level, all-fiber supercontinuum source based on telecom-grade fiber components", Appl. Phys. B 109, 177 (2012). CrossRef O. Traxer and E. X. Keller, "Thulium fiber laser: the new player for kidney stone treatment? A comparison with Holmium:YAG laser", World J. Urol., 1-12 (2019). CrossRef M. Michalska, et al. "Highly stable, efficient Tm-doped fiber laser—a potential scalpel for low invasive surgery", Laser Phys. Lett. 13, 115101 (2016). CrossRef R. L. Blackmon et al. "Thulium fiber laser ablation of kidney stones using a 50-μm-core silica optical fiber", Opt. Eng., 54, 011004 (2015). CrossRef A. Zajac et al. "Fibre lasers – conditioning constructional and technological", Bull. Pol. Ac.: Tech. 58, 491 (2010). CrossRef C. Guo, D. Shen, J. Long, and F. Wang, "High-power and widely tunable Tm-doped fiber laser at 2 \mu m", Chin. Opt. Lett. 10, 091406 (2012). CrossRef F. Liu et al. "Tandem-pumped, tunable thulium-doped fiber laser in 2.1 μm wavelength region", Opt. Express 27, 8283 (2019). CrossRef H. Ahmad, M. Z. Samion, K. Thambiratnam, and M. Yasin, "Widely Tunable Dual-Wavelength Thulium-doped fiber laser Operating in 1.8-2.0 mm Region", Optik 179, 76 (2019). CrossRef N. M. Fried, "Thulium fiber laser lithotripsy: An in vitro analysis of stone fragmentation using a modulated 110‐watt Thulium fiber laser at 1.94 µm", Lasers Surg. Med. 37, 53 (2005). CrossRef N. M. Fried, "High‐power laser vaporization of the canine prostate using a 110 W Thulium fiber laser at 1.91 μm", Lasers Surg. Med. 36, 52 (2005). CrossRef E. Lippert et al. "Polymers Designed for Laser Applications-Fundamentals and Applications", Proc. SPIE 6397, P639704 (2006). CrossRef N. Dalloz et al. "High power Q-switched Tm3+, Ho3+-codoped 2μm fiber laser and application for direct OPO pumping", Proc. SPIE 10897, 108970J (2019). CrossRef N. J. Ramírez-Martinez, M. Nunez-Velazquez, A. A. Umnikov, and J. K. Sahu, "Highly efficient thulium-doped high-power laser fibers fabricated by MCVD", Opt. Express 27, 196 (2019). CrossRef T. Ehrenreich et al. "1-kW, All-Glass Tm:fiber Laser", Proc. SPIE 7580, 758016 (2010). DirectLink L. Shah et al. "Integrated Tm:fiber MOPA with polarized output and narrow linewidth with 100 W average power", Opt. Express 20, 20558 (2012). CrossRef H. Zhen-Yue, Y. Ping, X. Qi-Rong, L. Qiang, and G. Ma-Li, "227-W output all-fiberized Tm-doped fiber laser at 1908 nm", Chin. Phys. B 23, 104206 (2014). CrossRef

Spectroscopy and 2 μm laser behaviors of Al3+/Ho3+ CO-doped silica fiber

A Ho3+-doped silica glass, 0.08Ho2O3–1.6Al2O3–98.32SiO2 (mol%), was prepared by the sol–gel method combined with high temperature sintering. The 2μm luminescence properties of the Al3+/Ho3+ co-doped silica core glass were investigated. A single-mode double cladding Al3+/Ho3+ co-doped silica fiber with a 15μm core diameter and 0.08 core numerical apertures was prepared. Pumped with a 1.95μm Tm3+ fiber laser, 320mw laser output centered at 2040nm with M2 factor of 1.14 was obtained from a 150-cm-long double-cladding fiber. The laser has a threshold of 850mw launched power with a slope efficiency of 48.46%. For the first time a robust single-mode 2μm fiber laser was realized in a fiber with Al3+/Ho3+ co-doped silica core glass prepared by the sol–gel method.

Investigation on Er3+/Ho3+ co-doped silicate glass for ~2 µm fiber lasers

A stable Er3+/Ho3+ co-doped lead silicate glass is developed. Luminescent properties are recorded under pumping with 808 and 1550nm lasers. Energy-transfer mechanism and efficiency are analyzed. Energy-transfer efficiency from Er3+:4I13/2 to Ho3+:5I7 reaches 93.8% at 3mol% Ho2O3 doping concentration. Strong luminescence is detected when pumped at 1550nm because of efficient energy transfer from Er3+:4I13/2 to Ho3+:5I7. Peak gain coefficient at 2056nm is detected as 1.62cm−1. The excellent luminescent property and high stability indicate that Er3+/Ho3+ co-doped lead silicate glass can be applied in 2µm fiber lasers.

Bismuth silicate glass: A new choice for 2 μm fiber lasers

We report on a new Yb3+/Tm3+/Ho3+ co-doped bismuth silicate glass: SiO2–Bi2O3–R2O (R=Li, Na, K) for 2μm fiber lasers. Bi2O3 was introduced into alkali silicate glass to optimize 2μm emission properties. Physical, chemical and spectroscopic properties of Yb3+/Tm3+/Ho3+ co-doped SiO2–Bi2O3–R2O (SBR) glass were presented. The Yb3+/Tm3+/Ho3+ co-doped SBR glass shows excellent thermal stability (ΔT=162°C), an intense 2.0μm emission pumped by 980nm LD with a lifetime of 1.33ms and width of 168nm, large maximum emission cross section of Ho3+ (5.3×10−21cm2), thus large σemτ product (7.049×10−24cm2s), which suggest its application in 2μm fiber lasers.

Graphene-based passively Q-switched 2 μm thulium-doped fiber laser

We demonstrated stable pulses generation at 2μm in a passively Q-switched thulium-doped fiber laser using a few layer graphene thin film. The maximum output power was 4.5mW and the single pulse energy was 85nJ at 53kHz repetition rate, and the pulse width was about 1.4μs. The pulse width and the repetition rate of the Q-switched fiber laser can be changed along with the pump power. To the best of our knowledge, this is the first report of graphene saturable absorber for passively Q-switched 2μm fiber lasers.

High-pulse-energy, actively Q-switched Tm^3+,Ho^3+-codoped silica 2μm fiber laser

A diode-pumped Q-switched Tm(3+),Ho(3+)-codoped double-clad silica fiber laser is reported providing average powers of up to 12.3 W at 2072.7 nm and stable pulse widths of only 45 ns and repetition rates in the range 10-100 kHz. Instabilities in pulse shape occur at nonoptimum cavity alignment and were found to be linked to the mechanism responsible for self mode locking.

Eyesafe Lasers and Their Applications. 2mm Eyesafe Fiber Lasers.

Research and development on 2μm eyesafe fiber lasers have been reviewed. The excellent laser performance of the high slope efficiency, low launched threshold power, and widely tunable range has been demonstrated in the rare-earth doped 2μm fiber lasers at room temperature.