Fig. 1. Structure of typical DBR-LD

Fig. 2. Reflectance spectrum of DBR grating

Fig. 3. Linewidth characteristics of single longitudinal mode DBR-LD at 1064 nm[24]

Fig. 4. Schematic of epitaxial structure of 635 nm DBR-LD [25]

Fig. 5. 3D structural diagram of DBR laser[29]

Fig. 6. DBR grating used for providing both high-reflection and optical confinement[31]

Fig. 7. 3D structural diagram of grooved single-mode laser[32]

Fig. 8. Ridge-curved waveguide grooved laser[33]. (a) 3D structural diagram; (b) SEM image of etched groove

Fig. 9. Working principle of resonant coupling cavity[35]

Fig. 10. Structural diagram of dual-wavelength DBR-LD[35]

Fig. 11. Dual-wavelength high-order DBR-LD [36]. (a) Structural diagram; (b) spectra at different injection currents

Fig. 12. Structural diagram of dual-mode DBR-LD[37]

Fig. 13. Structural diagram of Y-branched dual-wavelength laser[38]

Fig. 14. Two different types of dual-wavelength diode lasers[41]. (a) Two DBR-RW-LD mini-array; (b) Y-branched DBR laser

Fig. 15. Structural diagram of tunable DBR-LD [44]

Fig. 16. Butt-joint interface between gain section and DBR grating section[45]

Fig. 17. Two-stage DBR-LD [47]. (a) Schematic; (b) spectrum of 13-channel wavelength measured when only DBR current is tuned

Fig. 18. Structural distribution of SG

Fig. 19. SG with linear structure[59]

Fig. 20. P-U-I curve when DBR grating tapered LD structure is included[61]

Fig. 21. Lateral layout of DBR tapered LD with tapered grating[64]

Fig. 22. Three lateral layouts of DBR tapered lasers[65]