Double Half-Wave-Coupled Rectangular Ring-FP Laser with 35×100GHz Wavelength Tuning

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 281μm and 305μm 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 100GHz spacing is achieved with side mode suppression ratio up to 40.5dB.