Fig. 1. Schematic structure of ECSL.

Fig. 2. Schematic of the spot-size converter based on ridge waveguides.

Fig. 3. (Color online) Fundamental TE mode at the both facets of the SSC. (a) Output of TE mode at section a in Fig. 2. (b) Input of TE mode at section b in Fig. 2.

Fig. 4. (Color online) Coupling efficiency under different waveguide structures (Structure 1: H = 3 μm, h = 2.5 μm, W = 5 μm; Structure 2: H = 4 μm, h = 3 μm, W = 5 μm; Structure 3: H = 5 μm, h = 4 μm, W = 7 μm; Structure 4: H = 6 μm, h = 4 μm, W = 7 μm).

Fig. 5. Schematic diagram of SOI ridge waveguide structure.

Fig. 6. (Color online) Total coupling efficiency C of different SOI waveguide structures. (a) H = 3 μm. (b) H = 4 μm. (c) H = 5 μm. (d) H = 6 μm.

Fig. 7. (Color online) Effect of coupling coefficient on linewidth characteristics of laser.

Fig. 8. (Color online) Normalized coupling power varied with the offset. (a) Vertical directions. (b) Horizontal directions (SOI waveguide of structure 4: H = 6 μm, h = 4 μm, W = 7 μm).