Fig. 1. Simulated (a) TM₀₀ and (b) TM₀₁ mode electric field distribution cross-sectional views of the device anti-reflective (AR) surface.

Fig. 2. (a) Schematic diagram of the device structure. (b) Cross-sectional view SEM image of the device: the regrown interfaces are highlighted by dashed lines.

Fig. 3. (a) Double-crystal XRD test result of the MBE-grown active region. The x axis is the angle relative to the diffraction peak of the InP substrate. The inset zooms into the substrate diffraction peak region (the red box), and the number is the measured full width at half-maximum (FWHM, unit: s) of the corresponding peak. (b) The AFM image of the sample surface after MBE growth: the surface roughness is measured with 0.160 nm root mean square (RMS).

Fig. 4. Light-current-voltage (solid lines) and the WPE-current (dashed lines) characteristics measured in (a) a pulsed mode (200 ns, 100 kHz, duty cycle 2%) at different temperatures and (b) a CW mode at 298 K.

Fig. 5. (a) Inverse differential external quantum efficiency versus inverse mirror loss for devices of different cavity lengths. The devices with lengths of 3, 4, and 5 mm were obtained from the same wafer. The cavity facets were not coated, and the reflectivity was calculated to be approximately 0.27 using Fresnel equations. (b) Temperature dependence of the threshold current and the slope efficiency. T₀ and T₁ are the characteristic temperatures for the threshold current density and the slope efficiency, respectively.

Fig. 6. Lasing spectra at different currents at room temperature (298 K).

Fig. 7. “Far-field” distribution in the (a) horizontal direction (perpendicular to the epitaxial growth direction) and (b) vertical direction (along the epitaxial growth direction) at different currents. (c) Laser beam near-field distribution and the M² of the light spot under different currents. The “near-field” was measured at the beam focal plane after a focusing lens. The tests were conducted in a CW mode, with the TEC temperature set to 298 K.