Fig. 1. (a) Field distribution and (b) normalized radial intensity distribution F(r) for a high-Q coupled mode at 1553.2 nm in a microring resonator with a radius of 12 μm, an inner radius of 5 μm, and a 2 μm directly connected output waveguide.

Fig. 2. (a) Schematic diagram of the microring laser connected with an output waveguide, and (b) a microscopic picture of a microring laser with a cleaved output waveguide.

Fig. 3. (a) Multimode fiber coupled power and the applied voltage versus continuous biasing current and (b) lasing spectrum at a continuous biasing current of 25 mA, for a 12 μm radius microring laser at TEC temperature of 290 K.

Fig. 4. Small-signal modulation responses for the 12 μm radius microring laser at biasing currents of 15, 18, 20, and 25 mA and TEC temperature of 290 K.

Fig. 5. Schematic diagram of the apparatus used for (a) the small-signal modulation response measurement and (b) the microwave signals generated by optical beam beating, for the microring laser subject to external optical injection.

Fig. 6. Lasing spectra and small-signal modulation responses for the microring laser under 1 mW optical injection at biasing current of 25 mA and TEC temperature of 290 K. The wavelength detuning values are −0.142, −0.131, −0.114, and −0.091  nm for (a) and (b), and 0.149, 0.120, 0.103, and 0.084 nm for (c) and (d).

Fig. 7. Lasing spectra and small-signal modulation responses for a microring laser under optical injection at the wavelength 1557.2 nm and optical powers of 0.4, 1, and 3 mW, for the microring laser at biasing current of 25 mA and TEC temperature of 290 K. (a) and (b) correspond to negative detuning operation with λI=1557.2  nm, while (c) and (d) correspond to positive detuning operation with λI=1557.5  nm.

Fig. 8. (a) Additional resonance peak frequencies and (b) the heights of resonance peaks versus detuning wavelength for a microring laser at injection powers of 0.4, 1, and 3 mW, under continuous biasing current of 25 mA and TEC temperature of 290 K.

Fig. 9. Microwave signals of the beat signal between the lasing mode and 1 mW injection optical wave for the cases with (a) the positive and (b) the negative detuning wavelengths, respectively, for the microring laser under the continuous biasing current of 25 mA and TEC temperature of 290 K.