Semiconductor laser diode controller and laser diode biasing control method

Multichannel laser diode apparatus, comprising:

• a plurality of laser diodes;
• a separate optical power sensor positioned near each of said laser diodes so as to receive a portion of the light emitted from said laser diode, said optical power sensor generating an optical power measurement signal corresponding to the optical power of the light received by said power sensor;
• a separate drive current circuit coupled to each said laser diode, each said drive current applying a separately specified level of drive current through a corresponding one of said laser diodes;
• and
• a single digital data processor, coupled to all of said optical power sensors and to all of said drive current circuits, which sets said specified drive current levels applied to said laser diodes and which receives said optical power measurement signals from said optical power sensors;
• said digital data processor being programmed to step said drive current for each laser diode through a sequence of values, to compute operating characteristics of each said laser diode based on received optical power measurement signals for each drive current value, and to select a drive current level for each said laser diode based on said received optical power measurement signals.

A controller for a laser diode having a back facet and a front facet, including:

• a back facet photodiode which receives light emitted from a laser diode's back facet and generates an optical power measurement signal corresponding to the optical power output by said back facet of said laser diode;
• a drive current circuit, coupled to said laser diode, which applies a specified level of drive current through said laser diode;
• and
• a digital data processor, coupled to said back facet photodiode and to said drive current circuit, which sets said specified level of drive current applied to said laser diode and receives said optical power measurement signal from said back facet photodiode;
• said digital data processor being programmed to step said drive current through a sequence of values, to compute operating characteristics of said laser diode based on received optical power measurement signals for each drive current value, and to select a drive current level for said laser diode based on said received optical power measurement signals.

A method of controlling a laser diode, the steps of the method comprising:

• applying a drive current to a laser diode so as to generate light;
• measuring said generated light's optical power;
• providing a digital data processor;
• and
• under control of said digital data processor, automatically stepping said drive current through a sequence of values, receiving said optical power measurement for each drive current value, computing operating characteristics of said laser diode based on said received optical power measurement for each drive current value, and selecting a drive current level for said laser diode based on said received optical power measurement signals.

A method of controlling a plurality of laser diodes, the steps of the method comprising:

• applying a separate drive current to each of a plurality of laser diodes, thereby causing each laser diode to generate light;
• measuring said generated light's optical power for each laser diode;
• providing a single digital data processor;
• and
• under control of said single digital data processor, automatically stepping said drive current for each laser diode through a sequence of values, measuring optical power for the light generated by each laser diode at each drive current value, computing operating characteristics of each said laser diode based on said measured optical power for each drive current value, and selecting a drive current level for each said laser diode based on said optical power measurements.