MULTIMODE INTERFERENCE COUPLERS FOR THE CONVERSION AND COMBINING OF ZERO-ORDER AND FIRST-ORDER MODES

Optical waveguide mode-combiners for fundamental and first-order modes , based on multimode interference (MMI) couplers are presented. These devices convert a fundamental mode into a transversal first-order mode and combine it in lossless fashion with a second fundamental mode. Th ey can separate zero- and first-order modes in a common waveguide and allow the splitting and combining of zero- and first-order modes with nonuniform power splitting ratios. Realizations in InGaAsP/InP are dem onstrated. These new components have successfully been integrated into all-optical switches and were found to have advantageous characterist ics in all-optical devices.