Monolithically integrated four-channel laser array based on high-order surface gratings for O-band CWDM systems

An O-band monolithically integrated four-channel laser array based on high-order surface gratings is demonstrated. The fabricated laser array exhibits a wide bandwidth of up to 60 nm, with threshold currents ranging from 17 to 25 mA and slope efficiencies between 0.22 and 0.29 W/A. At an injection current of 200 mA, all side-mode suppression ratios (SMSRs) are above 40 dB, and the output power exceeds 36 mW. The high-order surface gratings are fabricated by standard lithography, which avoids high-precision lithography and a complex regrowth technique. A potentially cost-effective light source for coarse wavelength division multiplexing (CWDM) systems is provided.