Semiconductor laser diode controller and laser diode biasing control method
DCFirst Claim
1. A controller for a laser diode, comprising:
- an optical power sensor which receives a portion of the light emitted from a laser diode and generates an optical power measurement signal corresponding to the optical power of the light received by said power sensor;
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 optical power sensor 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 optical power sensor;
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.
6 Assignments
Litigations
0 Petitions
Accused Products
Abstract
A laser diode controller uses a programmed microcontroller to accurately control the process of turning on and selecting the operating point of the laser diode. The laser diode has a front facet for transmitting light, and a back facet for monitoring the laser diode'"'"'s optical output power. Once the back facet of the laser diode is calibrated, the controller can accurately monitor the laser diode'"'"'s operating characteristics, and can select the best operating point current based on the current operating characteristics of the laser diode. During calibration of the laser diode, the controller can check the linearity of the laser diode'"'"'s optical output power as a function of drive current, and can thereby detect defects in the laser diode. In a full duplex optical link, the controller of the present invention prevents the laser diodes from generating light at their full normal intensity until the integrity of the link has been established, thereby preventing light from the laser diode'"'"'s from accidentally damaging user'"'"'s eyes. Furthermore, the controllers can use the full duplex link to establish lower operating point drive currents that would otherwise be used, thereby significantly lengthening the lifetime of the laser diodes. A laser diode'"'"'s operating characteristics change over time in such a way as to enable the controller to predict when the laser will fail. The controller records the operating characteristics of the laser diode in a nonvolatile memory, analyzes changes in those characteristics, and generates a failure warning message when those changes match predefined failure prediction criteria.
-
Citations
25 Claims
-
1. A controller for a laser diode, comprising:
-
an optical power sensor which receives a portion of the light emitted from a laser diode and generates an optical power measurement signal corresponding to the optical power of the light received by said power sensor; 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 optical power sensor 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 optical power sensor;
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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
-
10. 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. - View Dependent Claims (11, 12, 13)
-
-
14. 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.
-
-
15. 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. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23)
-
-
24. 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. - View Dependent Claims (25)
-
Specification