Fig. 1. (a) 2D structures used in the thermal simulation. (b) 2D temperature distributions at dissipated power of 20 mW for the hybrid microring lasers with the radius R=20  μm and the ring width d=3.5  μm.

Fig. 2. Thermal resistance Ith and active region temperature rise ΔT at current density of 1  kA/cm2 versus microring width d for the 20 μm radius microlaser.

Fig. 3. (a) Calculated threshold current Ith versus microlaser radius R at different ring width d. (b) Threshold currents Ith versus the microring width d at R=20  μm, as the circles and the squares, with and without the heating effect, respectively.

Fig. 4. Calculated threshold current versus the stage temperature rise for microring resonators with the radius of 30 μm and the ring width of 2, 3, and 5 μm, respectively.

Fig. 5. (a) Cross-sectional view of the microring laser used in the 3D FDTD simulation. (b) Calculated output coupling efficiency η and scattering loss αbot caused by outer-bottom contacting layer versus the outer-bottom contacting layer thickness hbot.

Fig. 6. (a) Cross-sectional field patterns of magnetic component Hz at y=0 for the vertically fundamental mode TE1,15 at h=50, 200, 350, and 500 nm and hbot=0. (b) Corresponding vertical normalized field amplitudes at x=1.25  μm, where Γ is the optical confinement factor in the active layer.

Fig. 7. Diagrams of the fabrication steps. (a) ICP etch to the BCB layer. (b) ICP etch to inner-bottom contacting layer and SiO2 insulating layer deposition. (c) n-electrode deposition. (d) p-electrode deposition.

Fig. 8. (a) Top view and (b) cross-sectional view SEM images of an AlGaInAs/Si hybrid microring laser vertically coupled to a silicon waveguide.

Fig. 9. Output power and applied voltage versus CW injection currents for the hybrid microring lasers with (a) outer-bottom contacting layer and Δ=500  nm, (c) inner-bottom contacting layer and Δ=500  nm, and (e) inner-bottom contacting layer and Δ=−100  nm. (b), (d), and (f) show the corresponding lasing spectra at 15 mA, respectively. Microring radius is 20 μm; ring width is 3.5 μm.

Fig. 10. (a) Output power from the silicon waveguide and applied voltage versus CW injection current at 8°C, 20°C, 35°C, 45°C and 55°C. (b) Lasing spectra at CW injection currents of 6 and 17 mA at 20°C for a microlaser with a radius 30 μm and a ring width of 3 μm.

Fig. 11. Lasing wavelength Δλ shift versus the injection power increment ΔP for the microring lasers with the radius of 20 and 30 μm, and the corresponding ring width of 3.5 and 3 μm.