Overcoming L-I kink effects in a laser diode feedback control
AssigneeJDS Uniphase Corporation
InventorsMichael L. Bortz, David G. Mehuys, Bernard G. Fidric, John deAndrea
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Abstract
The negative effects of kinking in the L-I characteristics of laser diode operation with respect to feedback control for laser diode current control is suppressed by either (1) combining the output of a plurality of laser diodes together or (2) by imparting a current modulation superimposed on the direct driving current of the laser diode in conjunction with a limited feedback bandwidth, or a combination of both approaches (1) and (2).
Claims7
A method of operating a laser diode in a manner that avoids L-I kink effects in the diode output the method comprising:
- providing a drive current to the diode to power the diode;
- generating a feedback signal in a feedback circuit having a limited frequency bandwidth, wherein a magnitude of the feedback signal is proportional to an output power of the diode;
- adjusting the drive current of the diode with the feedback signal so as to maintain a predetermined diode output power;
- and
- dithering a magnitude of the drive current at a dither frequency that is higher than the frequency bandwidth of the feedback circuit.
A laser diode control apparatus for which L-I kinks are suppressed, the apparatus comprising:
- at least one laser diode source providing a light output;
- a driver circuit providing an operating current to said source;
- a feedback circuit that provides a feedback signal to the diode that is proportional to an output power of the diode;
- and
- a dither signal generator that generates a dither signal that dithers a magnitude of the drive current, the dither signal generator having a modulation depth control that allows a magnitude of the dithering to be adjusted, the dither signal having a frequency that is higher than a frequency bandwidth of the feedback circuit.
Dependencies are inferred from the claim text.