| 摘要 |
PURPOSE:To make the mounting of a calibration plate easy, and obtain a laser light wherein astigmatic difference which is different chip by chip is calibrated with high accuracy, by arranging a calibrating plate wherein a zone plate to calibrate the astigmatic difference is formed in the approximately vertical direction to an optical axis. CONSTITUTION:A semiconductor laser device has a chip 20 with an astigmatic difference DELTAL, and this chip 20 is mounted on a supporting stand 21 having a heat dissipation function. A cap 23 is provided with a light-transparent window 24 having a angle of theta2 ( 90 deg.) to an optical axis H, and a calibrating plate 25 Which is transparent to light is mounted on the window 24 with a distance D from a chip 20. The calibrating plate 25 makes the astigmatic difference DELTAL of a laser light output from the chip 20 zero, and has a collimation function to make said laser light a parallel ray. It is composed of light-transparent parallel plates made of glass, sapphire, etc., and a concentric circular stripe pattern formed on the surface of the parallel plates, that is, a zone plate. |
