Extension of operation range of semiconductor optical add and drop multiplexer

The contra-directional coupling between waveguides with a large difference of effective refractive index, /spl Delta/n/sub eff/ was investigated in order to extend operation range of an optical add and drop multiplexer, which consists of vertically stacked semiconductor waveguides. Numerical calculations and experiments were performed, and the operating range of the device was successfully extended to more than 40 nm by using a dissimilar waveguides with a /spl Delta/n/sub eff/ of 3%.