Tunable semiconductor laser based on surface high-order Bragg gratings with 62×50 GHz wavelength tuning

A tunable semiconductor laser based on surface high-order Bragg gratings with 50 GHz channel spacing is demonstrated for the first time. The tunable semiconductor laser can cover 62 channels at 25 °C, and the side mode suppression ratio (SMSR) of each channel is larger than 34 dB. To achieve such properties, the number, depth and periods of the slots of the tunable semiconductor laser are optimized by the 2-D scattering matrix method (SMM) to obtain denser reflection peaks with smaller full width at half maximum (FWHM) and higher reflectivity. The tunable semiconductor laser can be widely used in dense wavelength division multiplexing (DWDM) systems and can provide a promising light source for photonic integrated circuits.