CROSSTALK REDUCTION IN INTERSECTING RIB WAVE-GUIDES

A numerical study of the throughput and crosstalk in intersecting semi conductor rib waveguides was carried out using the beam propagation me thod, The fraction of the optical power that couples out of one input waveguide and into the crossed waveguide falls to below two percent fo r crossing angles greater than four degrees, A simple modification to the waveguide shape at the X-crossing region was found to reduce the c rosstalk for crossing angles between four and ten degrees, The crossta lk to throughput ratio is reduced by up to a factor of nine while the throughput is reduced by, at most, a few percent, In device structures that combine X-crossings with curved waveguide sections this permits greater design flexibility and improved overall loss and crosstalk per formance.