Characteristics Of Semiconductor-coupled Microdisk Cavity Mode

Semiconductor microcavity layers have many advantages such as ultrasmall volume and ultralow threshold. They have great potential applications in optoelectrinics integration. As one of the important types of microcavity lasers, microdisk lasers have been investigated all over the world. Recently, evanescent-coupled microdisks have attracted a great attention, because they can be fabricated easily by the lithographic technique.Numerical simulation is the fabricate elements for the semiconductor microdisks. In this paper, The mode characteristics for twin coupled microdisks are investigated by 2-D finite-difference time-domain(FDTD) technique. In the two coupled micodisks, mode coupling between the same order whispering-gallery modes (WGMs) results in coupled WGMs with split mode wavelengths. The numerical results show that the split mode wavelengths of the coupled first and second order WGMs can have a cross point in some case.For the two coupled microdisks with the radius R = 1μm and the refractive index n = 3.2. The anti-crossing coupling exists between the coupled WGMs TE9,1 and TE6,2 for the field pattern is symmetry to the Y axis. When change n to 2.8. The mode wavelengths of the two coupled WGMs TE9,1 and TE6,2 have a cross point in some place. When change R. The mode coupling between the first and the second WGM is existent too.The mode coupling between the first and the second order WGMs can greatly reduce the mode Q-factor of the coupled first order WGMs. So we can avoid these phenomena when fabricate semiconductor coupled microdisks.