Patent ID: 6885685
Filing Date: 2005-04-26
Classification: H01S

Abstract:
1. A method of controlling a semiconductor laser diode for emitting light with a predetermined optical output power and an extinction ratio by supplying a bias current and a modulation current thereto, the laser diode being installed in a laser module having a data storage and a means for monitoring a portion of the light emitted from the laser diode, the method comprising the steps of: (a) storing a plurality of parameters into the data storage, the parameters defining a specific function that relates one of the bias current and the modulation current to the other current, thereby the laser diode emitting light with the predetermined optical output power and the extinction ratio; (b) monitoring a photo current generated by the monitoring means, the photo current corresponding to the optical output power of the laser diode; (c) comparing the photo current with a target photo current; (d) changing one of the bias current and the modulation current by a prescribed magnitude; (e) calculating the other current based on the specific function characterized by the plurality of parameters; (f) supplying the bias current and the modulation current to the laser diode; and (g) iterating the steps from (b) to (f) until the optical output power and the extinction ratio of the laser diode become predetermined values.