Growth and decay of the electrooptic effect in thermally poled B/Ge codoped fiber

Using an in situ technique for measuring the induced electrooptic effect du ring poling, we have studied the growth and decay characteristics of therma lly poled twin hole B/Ge codoped fiber devices. The decay characteristic me asured at elevated temperatures were best fitted with a stretched exponenti al function, indicating a distribution of relaxation times is present in th is material. Using the Arrhenius relation, we calculate an activation energ y for the stability of the electrooptic effect with this material and polin g geometry in the range from 25 to 28 kJ/mol (0.28-0.31 eV), corresponding to a lifetime at 298 K of approximately 45 days.