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Photodarkening in Yb doped fibers: experimental evidence of equilibrium states depending on the pump power
Photodarkening in Yb doped fibers was examined at 633 nm insitu during cladding pumping at 915 nm with varying pump powers and with no indication of an onset threshold. For the first time, the partial...
PublicationsPhotodarkening kinetics as a function of Yb concentration and the role of Al codoping
We investigated the photodarkening (PD) kinetics of two fiber series with variation of the Yb content for constant host glass composition or constant ratio of Al/Yb, respectively. The results show the...
PublicationsIn-Fiber Temperature Measurement during Optical Pumping of Yb-doped Laser Fibers
The knowledge of temperature effects in rare-earth doped fibers is of great interest in order to improve the performance and stability of monolithic fiber lasers and fiber amplifiers. Fiber Bragg gratings...
PublicationsGrowth Characterization of Fiber Bragg Gratings Inscribed in Different Rare-earth-doped Fibers by UV and VIS Femtosecond Laser Pulses
Besides well-known applications of fiber Bragg gratings (FBGs) in sensing and telecommunication, current research focuses also on an integration of gratings in actively doped fibers in order to realize...
PublicationsApplicability of input coupling taper transitions for supercontinuum generation in nanoscale all-normal dispersion optical fibers
Supercontinuum generation in nanoscale all-normal dispersion optical fibers requires special attention concerning the input coupling of light due to the small core size. Preceding taper transitions along...
PublicationsInscription of first order Volume-Bragg-Gratings in a non-photosensitive material by using femtosecond-pulses with a wavelength of 400 nm
Volume-Bragg-Gratings were inscribed in glass by using a femtosecond-pulses to overcome the limitation of photosensitive materials. For inscription a wavelength of 400 nm was chosen to fabricate first...
PublicationsCombination of the resolution enhancing image inversion microscopy with digital holography
We propose a method to combine image inversion microscopy (IIM) with digital holography. By using this technique we are able to avoid some disadvantages of the IIM, like the use of a stabilized image inversion...
Publications193 nm absorption behavior in medium-to-high OH containing fused silica – The role of the initial ODC, OH and H2 contents
In the initial stage of low fluence ArF laser long term irradiation the absorption behavior in medium-to-high OH containing fused silica materials ([OH] = 250…1400 wt-ppm) depends on the OH content as...
PublicationsComparison of different design concepts for large mode area optical fibers
We present a comparison of different fiber designs with respect to bend sensitivity and effective mode area for high power transmission applications.
PublicationsSpatially resolved investigation of the oil composition in single intact hyphae of Mortierella spp. with micro-Raman spectroscopy
Zygomycetes are well known for their ability to produce various secondary metabolites. Fungi of the genus Mortierella can accumulate highly unsaturated lipids in large amounts as lipid droplets. However,...
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