Double Half-Wave-Coupled Rectangular Ring-FP Laser With <inline-formula> <tex-math notation="LaTeX">$35\times 100$ </tex-math></inline-formula>GHz Wavelength Tuning

Abstract

A widely wavelength tunable semiconductor laser based on two cascaded half-wave-coupled rectangular ring resonators is demonstrated. Vernier effect between two rectangular rings with perimeter of 281 and 305 $\mu \text{m}$ is employed to enlarge the tuning range. Simple fabrication process is used with all active waveguides. No epitaxial regrowth, grating, or high-resolution lithography is needed. By adjusting the injection currents applied to the cascaded rectangular rings synchronously, wavelength tuning of 35 channels with 100 GHz spacing is achieved with side mode suppression ratio up to 40.5 dB.