Spatial and spectral imaging of LMA photonic crystal fiber amplifiers

摘要

We demonstrate modal characterization using spatial and spectral resolved (S~2) imaging, on an Ytterbium-doped large-mode-area photonic crystal fiber (PCF) amplifier and compare results with conventional cut-off methods. We apply numerical simulations and step-index fiber experiments to calibrate our mathematical and experimental routines of our S~2 imaging system. We systematically analyze higher order mode (HOM) content of a polarizing 40/xm core double-clad PCF amplifier with various launching and coiling configurations. We demonstrate a HOM suppression of more than -24dB with variance of 2.3dB.