1,720,972 research outputs found
Q-switched 980nm Yb-doped fiber laser
No full textA Q-switched 980nm cladding-pumped ytterbium-doped single-mode fiber laser reached 1.2µJ of energy and 100W of peak power in 20ns pulses and repetition rates of 0.65MHz at 0.25W of average output power
Cladding-pumped Raman fiber amplifier
No full textCladding-pumped rare-earth-doped fibers and Raman fiber devices have been two of the most compelling advances in the area of high-power fiber amplifiers and lasers in recent years. Cladding-pumping enables pumping with multi-mode pump sources that deliver high-power at a low cost. The core of the double-clad fiber can still be single-moded, so that single-mode amplification or lasing can be realized. Raman gain requires high pump powers and Raman conversion is therefore only efficient at high power levels. On the other band, Raman devices are very flexible as gain is available at arbitrary wavelengths with the right pump source. Cladding-pumped Raman fiber devices represent a natural progression to multi-mode pumping and Raman fiber devices. While cladding-pumped Raman fiber devices require pump powers of, say, 100 W, such powers are available from fiber sources as well as from traditional bulk sources. For example, a multimode Nd-doped fiber laser with 1 kW of output power was recently reported. With pulsed sources, however, the required peak powers can be achieved with relatively modest average powers. Here, we report for the first time Raman amplification in a cladding-pumped fiber, without any rare-earth doping. We believe that this is an important step towards a whole class of new optical amplifier devices based on brightness-enhancing nonlinear conversion of multimode pumps, including not only Raman converters but also Brillouin and optical parametric converters
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Efficient Yb doped cladding-pumped fiber laser by a spectral beam-combined stripe-pump diode
No full textWe demonstrated an efficient Yb-doped clad pumped fiber laser with a high brightness-pumping source, which was a spectral beam combined striped diode laser at 977nm. The diode pump beam quality was much improve (M2=3.8) allowing efficient light coupled into small innercladding dimensions. As a result, we obtained an slope efficiency of 92% in the YDFL of 22 microns inner cladding diameter at 1040nm
High-power wavelength-tunable cladding-pumped rare-earth-doped silica fiber lasers
No full textWe describe the design and performance of cladding-pumped silica fiber lasers with high continuous-wave output powers and broad wavelength tunability in the 1, 1.5, and 2 µm spectral ranges. An ytterbium-doped fiber laser was tuned via wavelength dependent feedback provided by an external cavity containing a diffraction grating from 1027 to 1105 nm at multi-watt power levels. Similarly, high output power and wide wavelength tunability from 1540 to 1600 nm and from 1860 to 2090 nm at multi-watt output power levels has been achieved in Er-Yb co-doped and Tm-doped silica fiber lasers, respectively. A neodymium doped fiber laser was tuned from 1057 to 1118 nm at a lower power level. Limiting factors and the prospects for further improvements in performance are considered
Raman amplification and pulsed lasing in cladding-pumped germanosilicate fiber
No full textWe report for the first time Raman amplification in a cladding-pumped fiber. The double-clad germanosilicate fiber was pumped by a Q-switched Er-Yb co-doped fiber laser at 1570 nm. The power conversion efficiency was up to 36%, with a slope of 64%
Tunable Tm-doped silica fibre laser
No full textWe report the continuous-wave operation of a Thulium-doped silica fibre laser, pumped at 1567 nm from an erbium/ytterbium-doped fibre laser. The quantum efficiency of 51 % (with respect to absorbed pump power) is obtained at a wavelength of 1830 nm. The laser can be tuned continuously from 1750 to 1880 nm using an external grating
Cladding-pumped continuous-wave Raman fiber laser
No full textWe report for the first time continuous-wave Raman lasing in a cladding-pumped fiber. The double-clad germanosilicate fiber was pumped by an Er/Yb co-doped fiber laser at 1545 nm. We obtained 3.4 W of output power at 1660 nm with a slope efficiency of 67%
Jacketed air-clad cladding pumped ytterbium-doped fibre laser with wide tuning range
No full textA tunable cladding-pumped ytterbium-doped fibre laser is presented. An air-clad inner cladding supported by a micro-structured silica mesh inside a silica jacket is used. A measured inner-cladding NA of 0.4 to 0.5 enables efficient pump launch into a 36 µm-diameter inner cladding. The small inner cladding area enables tuning from 1010 to 1120 n
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