Fig. 1. Schematic of three-active-region lasers based on epitaxially-stacked structure

Fig. 2. Refractive index, fundamental mode and the first mode distribution of double-active-region lasers

Fig. 3. Refractive index profile, near-field optical intensity of fundamental mode, doping concentration and free carrier absorption loss distribution in each region of three-active-region lasers

Fig. 4. Diagram of the far-field divergence patterns of calculated and measured three-active-region lasers

Fig. 5. Typical P-I characteristics of laser diodes adopting epitaxially-stacked structure with 3 emitters and traditional structure with a single emitter in a pulsed mode (150 ns, 6.67 kHz), embedded diagram of the upper left corner shows the detected pulsed laser optical power signal