A new technique is presented to make vertically coupled semiconductor micro
ring resonators that eases the fabrication process with devices more robust
to ring-to-waveguide misalignments, Single-mode microring optical channel
dropping filters are demonstrated for the first time in this configuration
with es greater than 3000 and an on-resonance channel extinction greater th
an 12 dB, A 1 x 4 multipiexer/demultiplexer crossbar array with second-orde
r microrings was also made and exhibited channel-to-channel crosstalk lower
than 10 dB.