Design considerations for multi-core optical fibers in nonlinear switching and mode-locking applications

摘要

We explore the practical challenges which should be addressed when designinga multi-core fiber coupler for nonlinear switching or mode-lockingapplications. The inevitable geometric imperfections formed in these fibercouplers during the fabrication process affect the performance characteristicsof the nonlinear switching device. Fabrication uncertainties are tolerable aslong as the changes they impose on the propagation constant of the modes aresmaller than the linear coupling between the cores. It is possible to reducethe effect of the propagation constant variations by bringing the cores closerto each other, hence, increasing the coupling. However, higher couplingtranslates into a higher switching power which may not be desirable in somepractical situations. Therefore, fabrication errors limit the minimumachievable switching power in nonlinear couplers.