Patent ID: 6185239
Filing Date: 2001-02-06
Classification: H01S

Abstract:
A semiconductor laser device, comprising:a semiconductor laser having a front end face from which a main laser beam is emitted and a rear end face from which a rear laser beam is emitted;a mount on which said semiconductor laser is disposed;a photodetector used for controlling an output from said semiconductor laser and also formed on said mount, wherein said photodetector is disposed to detect a main laser beam emitted from said front end, but said photodetector is not located in the path of said main beamwherein,assuming that a critical angle at which a main beam of said semiconductor laser is completely reflected by a tip end of said mount where said photodetector is disposed is .theta., a numerical aperture of an optical system for collecting the main beam from said semiconductor laser is N.A. and refractive index of a surrounding medium is n, then said .theta. satisfies the relationship.theta.>.alpha. where (.alpha.=sin.sup.-1 (N.A./n)).