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

摘要

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.