Patent ID: 6324197
Filing Date: 2001-11-27
Classification: H01S

Abstract:
A power controller for a semiconductor laser device including a laser diode and an internal photodiode integrally assembled in a small substrate, which comprises:an electric current power source that electrically energizes said laser diode, an output power of said laser diode being detected as a first electric current detection signal by said internal photodiode;an external photodiode that detects an output power of said laser diode as a second electric current detection signal;a feedback controller that controls said electric current power source on the basis of one of said first and second electric current detection signals; anda determiner that determines whether an operation of said external photodiode is proper and normal,wherein the controlling of said electric current power source by said feedback controller is based on said second electric current detection signal when it is determined by said determiner that the operation of said external photodiode is proper and normal, andwherein the controlling of said electric current power source by said feedback controller is based on said first electric current detection signal when it is determined by said determiner that the operation of said external photodiode is improper and abnormal.