Abstract

We address the problematic of co-propagative evanescent coupling interactions between fast and slow modes in guided optics. The analysis is performed in the case of an asymmetric directional coupler assisted by a Bragg grating (BG). It is shown, that the evanescent coupling of a fast mode to a slow mode occurring in the vicinity of a BG band gap, is subjected to the fulfillment of a certain threshold condition on the BG coupling coefficient. The phase matching analysis results are confirmed by the coupled mode theory four-wave modeling applied to describe the behavior of the investigated device.

© 2012 Optical Society of America