Abstract

The presence of defects in glass optical fibers is considered a key factor for the observation of photoinduced SHG.¹ Most studies have ben concerned with Ge-doped silica fibers in which Ge-defects are the active species. Recently we have reported photoinduced SHG in rare earth-doped optical fibers that do not contain Ge.² Conversion efficiencies in such fibers exceed those observed in most Ge-doped fibers. In an aluminosilicate fiber doped with 0.008 wt.% Ce we have observed SHG conversion efficiencies of 1.5% at input infrared peak powers of 200 W. We have investigated the dependence of the SHG efficiency on Ce concentration. Permanent χ⁽²⁾ gratings were written with infrared (1.06 μm) and green (0.532 μm) light (seeded SHG) in 40-cm lengths of fiber. We discuss the SHG results as well as the luminescence spectra excitation at 1.06 μm for fibers with varying Ce concentration. Finally we have studied fibers doped with other rare earth ions and we compare their behavior with that of the Ce-doped fibers.

© 1991 Optical Society of America