Fig. 1. Structural design of laser. (a) Schematic diagram; (b) refractive index distribution and light field distribution

Fig. 2. Experimental results. (a) Light field distribution within single grating period; (b) relationship between number of grating pairs and grating loss

Fig. 3. Regulatory effect of designed structure on lateral mode. (a) Transverse optical field distributions of different laser modes;

Fig. 4. Optical power and voltage versus operating current for lasers under continuous wave operating condition at room temperature

Fig. 5. Laser spectraandbandwidth under continuous current operating condition at room temperature. (a) Laser spectra; (b) bandwidth

Fig. 6. Far-field divergence angles of laser under continuous current operating condition at room temperature. (a) Slow-axis divergence angle; (b) fast-axis divergence angle

Fig. 7. Near-field characteristics of lasers under continuous current operating condition at room temperature. (a) Bias current of 1 A; (b) bias currentof2 A

Fig. 8. Transverse BPP values of lasers under different x