Fig. 1. Schematics of semiconductor laser structure. (a) Device structure; (b) epitaxial structure

Fig. 2. Experimental setup diagram for measuring semiconductor laser output facet temperature based on optical-thermal reflection

Fig. 3. Measurement results of thermal reflection coefficient of output facet of semiconductor laser. (a) Epitaxial layer; (b) substrate

Fig. 4. Collected facet images and processed thermal images. (a) Thermal images; (b) cold image; (c) variation distribution of facet reflectivity; (d) facet temperature image after processing

Fig. 5. Facet temperature distributions under different iteration numbers. (a) 1 iteration; (b) 10 iterations; (c) 100 iterations; (d) 1000 iterations

Fig. 6. Relationship between thermal reflection signal fluctuation and iteration number. (a) N=10⁰; (b) N=10¹; (c) N=10²; (d) N=10³

Fig. 7. Schematics of semiconductor laser chip welding, packaging, and installation on test fixture. (a) Semiconductor laser is mounted on test fixture; (b) semiconductor laser chip is welded on heat sink using P-down packaging method

Fig. 8. Variation of facet temperature distribution on epitaxial layer with operating current

Fig. 9. Facet temperature distributions in slow axis direction under different currents

Fig. 10. Measurement results of semiconductor laser junction temperatures. (a) Variation of lasing wavelength with operating temperature (I=10 A, continuous wave mode); (b) variation of lasing wavelength with waste heat power (T_HS=25 ℃); (c) LIV curves of semiconductor laser (T_HS=25 ℃)

Fig. 11. Distributions of output facet temperatures along fast axis under different currents