Sensitivity of two core fiber coupling to light-induced defects

Abstract
Permanent changes in the refractive index of a germania-doped silica core fiber nonlinear directional coupler exposed to 620-nm wavelength high-intensity 100-fs pulses are discussed. The index change, on the order of 10/sup -5/, is estimated from the detuning aspects of the coupler. Both the constraints and beneficial aspects of these defects for nonlinear optical devices are discussed.