The second-order Bragg grating structure of an 808 nm distributed feedback semiconductor laser diode was designed and optimized.The grating with a period of 240 nm was fabricated on GaAs substrate by holographic photolithography and wet etching.Images of optical microscopy,scanning electron microscopy and atomic force microscopy show that the grating has a period of 240 nm,duty cycle of 0.25,depth of 80 nm,with perfect surface morphology,good fringe continuity and uniformity. The second-order Bragg grating structure of an 808 nm distributed feedback semiconductor laser diode was designed and optimized. The grating with a period of 240 nm was fabricated on GaAs substrate by holographic photolithography and wet etching. Images of optical microscopy, scanning electron microscopy and atomic force microscopy show that the grating has a period of 240 nm, duty cycle of 0.25, depth of 80 nm, with perfect surface morphology, good fringe continuity and uniformity.