Photoinduced second-harmonic generation and luminescence of defects in Ge-doped silica fibers

摘要

We have measured the efficiency of photoinduced second-harmonic generation (SHG) in Ge-doped silica fibers containing different concentrations of 'GeO' and 'GeH' defects. The relative concentration of these defects were varied by heat treatments in H$-2$/ and determined using luminescence spectroscopy. The results show that the GeH defect center, which can be excited in the visible (around 500 nm) and luminescence around 700 nm, plays a role in the photoinduced SHG process. On the other hand, the results do not allow us to rule out contributions from the GeO defects.