Fig. 1. (a) The simulation model; (b) schematic diagram of simplified facet; (c) schematic diagram of asymmetric structure; (d) linear and parabolic refractive index distributions

Fig. 2. Reflectivity of optical films on various-sized facets at 980 nm. (a) AR film; (b) HR film

Fig. 3. The reflection curves of AR film. (a) Single-layer; (b) double-layer

Fig. 4. Reflectivity of HR film under different HL logarithms, the insert is the reflection curves of 5 pairs of HR film

Fig. 5. Reflectivities of different optical films on ASOC and SOC facets. (a) AR film; (b) HR film

Fig. 6. Reflectivity sweep at various film thicknesses. (a) AR film; (b) HR film

Fig. 7. Reflection curves of optical films before and after optimization. (a) AR film; (b) HR film

Fig. 8. Reflection curves of optimized optical films on GaAs wafer. (a) AR film; (b) HR film

Fig. 9. Surface images of the optical film

Fig. 10. Statistical diagram of LD parameters of single facet coating. (a) Output power of the front and rear facets; (b) power ratio of the front and rear facets

Fig. 11. (a) Superradiation spectrum and (b) statistical diagram of the ripple index

Fig. 12. Performance of ECL with optimized optical films (a) Spectrum curve; (b) power-current-voltage (PIV) curve