Abstract

Since the discovery of second-harmonic generation (SHG) in germanosilicate optical fibers only two other glass materials have exhibited efficient SHG and only one other fiber system. Semiconductor microcrystallite-doped glasses produced optically encoded SHG in bulk and in ion exchanged waveguides while Ce³⁺-doped aluminosilicate glass produced SHG in optical fibers. The discovery of new glasses is of paramount importance to understanding this problem and to the possibility of a unified understanding of the effect in the various materials. We have recently discovered that silica fibers with Eu²⁺-doped (200 ppm) aluminosilicate (3 wt.%) core can be prepared for SHG using a cw model-locked (76-MHz) laser operating at 1.06 μm. Fibers with 11.5-μm core diameter were prepared by simultaneous exposure to average intrafiber powers of 8 W and 30 W at 1.06 μm and 532 nm, respectively. The fiber was prepared by launching into the LP⁰¹ mode for both fields. The prepared fiber exhibited an ultrastable (<5%) output at 532 nm with a conversion efficiency of 1.5 × 10^-4 with 8 W of IR average readout power. Of particular interest is that a sharp IR preparation intensity behavior is observed at around the same value found in germanosilicate glasses (~1 GW/cm²). Finally, the fiber could be erased over periods of minutes using 488-nm light from an argon-ion laser.

© 1991 Optical Society of America