Fig. 1. Schematic diagram of an unsynchronized coupled grating. (a) Three dimensional stereogram; (b) side view; (c) top view

Fig. 2. Comparison between simulation and calculation of lateral asymmetric grating reflectance changes with different ridge widths. (a) w=20 μm; (b) w=5 μm; (c) w=2 μm

Fig. 3. Transverse spot distribution at different positions of lateral asymmetric grating. (a1) (b1) Ⅰ; (a2)(b2) Ⅱ; (a3)(b3) Ⅲ; (a4)(b4) Ⅳ

Fig. 4. Longitudinal optical field distribution in a resonator cavity of lateral asynchronous coupled DFB semiconductor laser. (a) Δz/Λ=0; (b) Δz/Λ=0.23; (c) Δz/Λ=0.43; (d) Δz/Λ=0.50; (e) Δz/Λ=0.58

Fig. 5. Relationship between grating reflectivity and ridge width. (a) Relationship between ridge width and grating reflectivity; (b) relationship between ridge width, asymmetric distance, and grating reflectivity (h=4 μm)

Fig. 6. Relationship between grating width, dislocation distance, and reflectivity (w=5 μm)

Fig. 7. Relationship between grating duty cycle, dislocation distance, and reflectivity (w=2 μm; h=4 μm)