Thulium-doped silica-based optical fibers for cladding-pumped fiber amplifiers (original) (raw)
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Fibers
In this work we report on the thulium-doped silica-based optical fibers with increased fluorescence lifetime of the 3F4 level thanks to the modification of the local environment of thulium ions by high content of alumina. The determination of the cross-relaxation energy-transfer coefficients from the measurements of the fluorescence lifetimes of the 3F4 and 3H4 energy levels of Tm3+ ions in the experimentally prepared optical fiber is provided as well. Preforms of optical fibers were prepared either by conventional solution-doping of Tm3+ and Al3+ ions or by dispersion-doping of Tm3+ ions with alumina nanoparticles. Optical fibers were characterized by means of Tm, Al, and Ge concentrations, refractive index profiles, optical spectral absorption and luminescence, and by time-resolved fluorescence spectroscopy. Highly aluminium-codoped thulium silicate optical fibers exhibited fluorescence lifetimes of over ~500 μs with maximum value of 756 μs, which means a fluorescence lifetime enh...
2012
Silica-based thulium-doped fiber devices operating around 810 nm would extend the spectral range covered by highpower fiber devices. Using a comprehensive numerical model of the fiber we have shown that efficient lasing at 810 nm can be achieved for specific ranges of the laser cavity parameters in silica-based thulium-doped fibers with enhanced 3 H 4 lifetime up to 58 µs as measured in our highly alumina-codoped fibers. We present optimization of the thulium-doped fiber and laser cavity parameters and also potential applications of the developed host material in amplifiers and broadband sources.
Broadband silica-based thulium doped fiber amplifier employing multi-wavelength pumping
Optics express, 2016
A multi-wavelength pumped thulium doped fiber amplifier is investigated to extend the spectral gain coverage of the amplifier in the 1.7-1.9μm wavelength range. Through the use of a combination of 791 nm, 1240 nm, and 1560 nm laser diode pumping, the amplifier gain can be improved significantly and overall gain bandwidth enhancement of ~47% as compared to single-wavelength pumping achieved. A nominal gain of 15 dB is achieved over a bandwidth of more than 250 nm spanning from 1700 to 1950 nm with a maximum gain of 29 dB and a noise figure of less than 5 dB.
Thulium-doped optical fibers for fiber lasers operating at around 2 µm
Bulletin of the Polish Academy of Sciences Technical Sciences
The paper deals with spectral and lasing characteristics of thulium-doped optical fibers fabricated by means of two doping techniques, i.e. via a conventional solution-doping method and via a nanoparticle-doping method. The difference in fabrication was the application of a suspension of aluminum oxide nanoparticles of defined size instead of a conventional chloride-containing solution. Samples of thulium-doped silica fibers having nearly identical chemical composition and waveguiding properties were fabricated. The sample fabricated by means of the nanoparticle-doping method exhibited longer lifetime, reflecting other observations and the trend already observed with the fibers doped with erbium and aluminum nanoparticles. The fiber fabricated by means of the nanoparticle-doping method exhibited a lower lasing threshold (by »20%) and higher slope efficiency (by » 5% rel.). All these observed differences are not extensive and deserve more in-depth research; they may imply a positive influence of the nanoparticle approach on properties of rare-earth-doped fibers for fiber lasers.
Photonics, Devices, and Systems V, 2011
Thulium-doped fibers suitable for core-pumped single-frequency lasers were fabricated by the modified chemical vapor deposition (MCVD) method. Refractive index profile, doping profile and spectral absorption was measured. High doping concentration of thulium ions should be achieved to allow for high absorption of light at a pump wavelength while the thulium ions clustering should be avoided to prevent the cooperative upconversion and quenching processes. The fabricated fibers featured pump absorption up to 70dB/m at a pump wavelength of 1611nm. The single-frequency master oscillator with a resonator composed of a pair of fiber Bragg gratings and a thuliumdoped fiber was demonstrated with predominantly single ended operation. We achieved a slope efficiency of 22% and a threshold of 22mW at a lasing wavelength of 1944nm.
IEEE Photonics Technology Letters, 2000
Signal amplification in the -and + -band is demonstrated for the first time by simultaneous pumping of thuliumdoped fiber amplifier (TDFA) with 690 and 1050 nm (or 1400 nm). Both pumping schemes are investigated and shown to be highly efficient: Roughly 20 dB of signal gain is available with only 80 mW of 1050 nm plus 42 mW of 690 nm, while signal input power is fixed at 35 dBm. Furthermore, these excitations can take advantage of low-cost readily available pump laser diodes at 690 nm for digital video disk applications. This makes TDFA a promising candidate for coarse wavelength-division-multiplexing applications in metropolitan area network and access network environment.
IEEE Photonics Technology Letters, 2000
We report on the characterization of a recently introduced dual-wavelength pumping scheme for thulium-doped fiber amplifiers using 800 and 1050 nm. Using a counterpropagating pump configuration, 180 mW of total pump power yielded 27-dB small-signal gain and less than 5-dB noise figure. Furthermore, using optical frequency domain reflectometry, the distributed gain in this configuration was evaluated, allowing for optimization of the doped fiber length.
Optics Express, 2011
A compact upconversion fiber laser operating around 810 nm is proposed using thulium-doped silica-based fiber with locally modified thulium environment by high alumina codoping. Using a comprehensive numerical model of thulium doped fiber we investigate performance of the proposed laser. Comparison with two other thulium hosts, fluoride glass and standard silica, is presented. Efficient lasing can be expected even for silica based fiber for specific ranges of the fiber and laser cavity parameters, especially when 3 H 4 lifetime is enhanced. With moderate pump power of 5 W at wavelength of 1064 nm, the predicted output power of the upconversion laser is about 2 W at 810 nm.
Model of the amplified spontaneous emission generation in thulium-doped silica fibers
Journal of the Optical Society of America B, 2012
A model of the ∼2 μm amplified spontaneous emission (ASE) generation in the thulium-doped silica fibers pumped at 1575 nm is presented. Both Al-codoped and Al/Ge-codoped fiber core compositions are studied. The results show that the composition affects the relative slope efficiency of 10% and the bandwidth of 19% of the output ASE. Our results predict that the backward ASE is more powerful and spectrally broader compared to the forward ASE, which is in agreement with previous experiments. Using an asymmetric cavity feedback, 98% of the total output power can be directed in the backward ASE, but with the consequence of losing ∼50% of the bandwidth. Such sources are expected to deliver single-mode output with more than 70% slope and 39% power conversion efficiency.