US Patent 7424044 Semiconductor laser device

The semiconductor laser device 1A has a semiconductor laser array 3 including a plurality of active layers 2 arranged in parallel along a slow direction, and outputs laser beams from the front end face 2a side of the active layers 2. The semiconductor laser device 1A comprises a collimating lens 5 that collimates laser beams L1 outputted from the respective rear end faces 2b of the active layers 2 within a plane orthogonal to the slow axis, and a reflecting mirror 9 that feeds back parts of the laser beams L2 outputted from the collimating lens 5 to the respective active layers 2 via the collimating lens 5.