GVD characteristics of two different large-mode-area double-clad fibers with defined launching pump laser power level were systematically analyzed. The dispersion parameters for different fiber designs and various doping levels are investigated over a broad spectral range in the emission area of Yb-doped fiber samples for controlled sets of operating parameters. The experiment utilizes a supercontinuum source developed within this laboratory as well as a Mach-Zehnder interferometer with a dual-channel spectral-detection system sensitive to wavelengths from 0.95 μm to 1.75 μm. Temporally resolved spectrograms recorded at distinct delay positions enable the detection of interference fringes for the equalization wavelength. By applying a Sellmeier polynomial fit to the wavelength dependent differential group-delay function, the GVD can be derived. The measured Yb-doped large-mode-area fibers show a variation of the doping concentration between 0.7 mass percent to 3 mass percent of ytterbium. The measurement of the Yb-doped large-mode-area fiber with or without optical load on the sample during the measurement was examined. |
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Optical fibers
Dispersion
Fiber lasers
Cladding
Velocity measurements
Doping
Absorption