Fig. 1. Schematic diagram of the coupled-cavity laser composed of an FP cavity and a square/rhombus microcavity as a deformed square microcavity with a vertex extending a distance of δ, and the wave vectors for the mode light rays reflected from the sides of the SRM and the square microcavity.

Fig. 2. Simulated reflectivity spectra at different gain levels obtained by FDTD simulation for an SRM connected to a vertex waveguide, with (a) the side length a=10  μm, the deformation amplitude δ=0.15  μm, and waveguide width d=2  μm and (b) a=15  μm, δ=0.25  μm, and d=2  μm, respectively. (c) Reflectivity for the modes α1, α2, α3, and η for the mode α1 versus the deformation amplitude δ for an HSRRL with a=10  μm, d=2  μm, and L=300  μm.

Fig. 3. Mode intensity profiles of Hz in the (a) HSRRL, (b) SRM, and (c) FP cavity, and (d) simulated far-field intensity at 1541.5 nm.

Fig. 4. Simulated far-field intensity profiles and mode intensity profiles of Hz of high-Q modes in the HSRRLs with a=10  μm, δ=0.15  μm, d=2  μm, and L=(a) 280 μm, (b) 290 μm, and (c) 310 μm, and the HSRL with a=10  μm, d=2  μm, and L=(d) 280 μm, (e) 290 μm, and (f) 310 μm. The proportions of the fundamental transverse mode in the FP cavity η are given for the coupled modes.

Fig. 5. Microscopic image of an HSRRL with patterned p-electrodes for current injection into the SRM and FP cavities separately.

Fig. 6. Output powers coupled into an SMF versus IFP as ISRM is fixed at different currents for HSRRLs at L=300  μm, d=2  μm, with (a) a=10  μm, δ=0.15  μm and (b) a=15  μm, δ=0.25  μm.

Fig. 7. Lasing characteristics with the variations of IFP and ISRM for the HSRRL with a=15  μm, δ=0.25  μm, d=2  μm, and L=300  μm. Lasing spectra (a) versus ISRM at IFP=64  mA and (b) versus IFP at ISRM=20  mA. Dominant lasing mode wavelengths and corresponding SMSRs (c) versus ISRM at IFP=64  mA and (d) versus IFP at ISRM=20  mA, respectively.

Fig. 8. Superimposed lasing spectra for HSRRLs at L=300  μm, d=2  μm with (a) a=15  μm, δ=0.25  μm and (b) a=10  μm, δ=0.15  μm, and their corresponding SMSRs and peak powers at (c) a=15  μm and (d) a=10  μm.

Fig. 9. Small single modulation responses of an HSRRL with a=15  μm, δ=0.25  μm, L=300  μm, and d=2  μm. (a) Small signal modulation responses at IFP=30, 40, and 70 mA; (b) fitted resonance frequency and 3-dB bandwidth vary by the square root of the injection current of the FP cavity and as a function of (IFP−Ith)1/2 at ISRM=5  mA.

Fig. 10. (a) 25-Gb/s and (b) 35-Gb/s eye diagrams for HSRRL with a=15  μm, δ=0.25  μm, d=2  μm, and L=300  μm at ISRM=14  mA and IFP=68  mA.