Four-channel directly modulated square-rectangular laser array in the O-band

A four-channel directly modulated square-rectangular laser array was demonstrated in 1.3 mu m wavelength range with the wavelength interval about 5 nm. The laser array shows stable single mode operation with the side-mode suppression ratio (SMSR) over 30 dB, 3-dB modulation bandwidth above 11.8 GHz and an open-eye diagram is obtained at data rates of 10 Gb/s, and the relative intensity noise (RIN) about -138 dB/Hz up to 5 GHz for all channels.