1,721,009 research outputs found
A Fermat's spiral multifilament-core fiber
No full textA multifilament-core optical fiber where the microstructure is arranged in a Fermat’s spiral is presented. The properties of such a fiber to be exploited for laser light amplification are numerically investigated by means of a full-vectorial finite-element method. Thanks to this peculiar microstructure, the fiber is shown to have an increased Brillouin threshold power and very low bending losses, while preserving a very good beam spatial quality
A Raman fibre amplifier generating simultaneous gain across multiple Stokes orders by using step shaped optical pulses
No full textOptical amplification based on stimulated Raman scattering (SRS) in optical fibres offers the potential to generate gain at any arbitrary wavelength with an appropriate pump source. This has proved a very effective and successful way of providing gain at those wavelengths not directly available with rare-earth doped fibres. However most of this success has been achieved using CW pump sources, but in recent years there has been renewed interest in the pulsed pumping of Raman amplifiers
Third harmonic generation in silica microfibres
No full textWe theoretically and experimentally study third harmonic generation in silica microfibres. Phase matching at critical diameters was achieved by intermodal-coupling with higher order third harmonic modes, which were successfully generated using 4ns 1.55µm pump pulses
Erbium-ytterbium co-doped hollow optical fibre laser
No full textAn erbium-ytterbium co-doped hollow optical fibre (HOF) laser generating up to 2.5 W of output power in the 1550 nm spectral region with a power conversion efficiency of 26% with respect to the launched pump power is demonstrated. A significant reduction of ytterbium co-lasing at 1060 nm is observed with increasing core thickness in the HOF, which is believed to be correlated with the signal overlap factor at 1550 nm that increases as the core thickness increased
A counter-propagating cascaded Raman fiber amplifier pulsed pumped with a 1.06 micron source
No full textWe report gain and noise measurements for a pulsed pumped cascaded Raman fiber amplifier with a counter-propagating signal. Gain is measured as high as the 7th order Stokes for different pulse duty cycles
High-energy in-fiber pulse amplification for coherent lidar applications
No full textAn Er:Yb codoped fiber amplifier chain for the generation of pulses for coherent lidar applications at a wavelength near 1.5 micron is reported. The final 1.8-m-long power amplification stage had a 50 micron core diameter and yielded a 23-dB energy gain, resulting in 0.29-mJ, 100-ns pulses at a repetition rate of 4 kHz with no Brillouin scattering and an M2 of 2.1
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
Tunable narrow linewidth high power erbium:ytterbium co-doped fiber laser
No full textWe present a narrow linewidth cladding-pumped erbium: ytterbium co-doped large-core fiber laser with output power up to 70W at 1560nm, and tunable from 1550 to 1602 nm using a narrow-band fiber Bragg grating
Picosecond Yb-doped single-trench-fiber amplifier with diffraction-limited output
No full textWe demonstrate a 30µm core single-trench fiber ensuring single mode output. This fiber design can be fabricated with conventional MCVD process in conjunction with solution doping process, which can dramatically reduce the fabrication cost, hence suitable for mass production. Meticulous measurements ensure a robust single mode. Furthermore, this fiber used in three stages MOPA provides 80kW peak pulses with repetition rate of 500 kHz, average power up to 10W, with M2 ~ 1.14. Moreover, all solid structure ensures easy cleaving and splicing. In nutshell, an Ultra-low cost, Monolithic, Compact, and an effective Single mode fiber amplifier device can be achieved using Single trench fiber
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