Wide wedge-shaped depletion region in thermally poled fiber with alloy electrodes

A twin-hole fiber was provided with Au-Sn alloy electrodes and thermally poled at 255 degreesC with 4.3 kV applied during 155 minutes. An electric field 6 x 10(7) V/m was recorded. The poled fiber was cleaved and etched, revealing that the depletion region overlapped the entire core, was wedge shaped and pointed towards the cathode. The recorded profile closely followed the spatial distribution of the poling field. (C) 2004 Optical Society of America.