Fig. 1. Schematic of the a microsquare resonator with a current injection window in the center and four corners

Fig. 2. Simulated magnetic field（|Hz|）distributions in the square microcavity with a = 30 μm and w_{g= 3 μm}

Fig. 3. Simulated wavelength intervals of the fundamental mode and the first-order mode versus Δn for the microsquare resonators

Fig. 4. Microscopic image of a square microcavity laser with a current injection window in the center and four corners

Fig. 5. Lasing characteristics of the square microcavity laser

Fig. 6. Variation of wavelength interval and refractive index step with injection current

Fig. 7. Wavelength interval versus the injection current for the square microlaser with a square-ring current injection window

Fig. 8. Fine spectra of a microcavity laser with a current injection window in the center and four corners