Directly modulated semiconductor lasers with surface high-order grating fabricated by standard photolithography

Directly modulated semiconductor lasers (DMLs) with surface high-order grating have been designed, fabricated and measured. The output powers under different temperatures were measured, and there are almost no kinks among all the light-power curves. The threshold current is 22 mA with a slope efficiency of 0.21 mW/mA at 25 ℃. The side-mode suppression ratio (SMSR) over 30 dB is achieved. The wavelength red-shifting caused by current-induced heating is at a ratio of 0.03 nm/mA. Small signal response of this kind of lasers with surface high-order grating was measured at 25 ℃ and the -3 dB bandwidth is 11 GHz.