The relationship between the Q factor and the self-coupling index of single straight waveguide microring resonator is studied by using coupling mode theory to realize high Q microring resonators.Then the resonators based on Si3N4 waveguides are fabricated by using CMOS compatible techniques with 2 μm wide waveguides and 200 μm in radius.The Q factor and its relation to the self-coupling index of the fabricated microring resonators are measured on the assumption that the resonators in the same ba...