Microcavities are fundamental building blocks for on-chip integrated photonic circuits. Till now, most of the microdisks (microrings) are coupled to the waveguides via the evanescent coupling, which is strongly restricted by the nanosized gap distance (between waveguide and cavity) and narrow bandwidth to realize the phase matching condition. In this talk, we will present our recent results on a brand new coupling mechanisms. Based on the time reversal process of laser, we show that the light can be efficientyl coupled into a silicon microdisk by simply connecting a waveguide onto it. The coupling efficiency and quality (Q) factors are ~ 60% and 7*10^5, respectively. As the new mechanism doesn't rely on the phase matching considtion, the high efficiency end-fire injection can be realized within a large range of waveguide width (> 500 nm), tilt angle, and spectral range, sigificnatly reducing the costs and expanding the potential applications of potential photonic devices.
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