Polarization properties of permanent and nonpermanent photorefractive gratings in hi-bi fibers

Abstract

The polarization properties of photorefractive reflecting gratings formed in Ge-doped high-birefringence (hi-bi) fibers by the internal method are presented. The gratings reflect only the polarization eigenmode used in fabrication and a polarization selectivity of 20 dB is demonstrated. It is also shown that there are two different photorefractive effects that can be used to write the gratings: one is permanent when heated to 240 degrees C, while the other is erasable.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>