Bistable Micro-Ring Lasers With Compact Footprint and High Output Efficiency

Micro-ring lasers, with a minimum bend radius of 10 $\mu{\rm m}$ , are presented that exhibit directional bistability and output powers up to 1.5 mW. In order to achieve devices with low threshold currents, mW output powers and directional bistability, the confilicting design constraints on the device are highlighted. Optimized adiabatic waveguide bends, bi-level evanescent couplers, and deeply etched ridge waveguide designs are presented in order to meet the stringent device design requirements. The optimized micro-ring laser devices exhibit directional extinction ratios of 25 dB and side-mode suppression ratios ${>}{\rm 25}~{\rm dB}$ .