Maintaining desirable performance of optical emitters at extreme temperatures
View Patent ↗A method of maintaining desirable optical performance of an optoelectronic apparatus at extreme temperatures is disclosed. At a first temperature, a first bias current at which the laser generates optical signals at a first level is determined. At a second temperature outside of a predefined range of the first temperature, a second bias current at which the laser generates optical signals at a second level is determined. If the second temperature is greater than the higher end-point temperature of the predefined range, the second predefined level is defined to be less than the first predefined level. If the second temperature is less than the lower end-point temperature of the predefined range, the second predefined range is defined to be greater than the first predefined level.
1. An optoelectronic apparatus comprising:
an optical emitter;
an emitter driver circuit coupled to drive the optical emitter;
a controller circuit coupled to the emitter driver circuit, the controller circuit configured to provide control signals to the emitter driver circuit to maintain consistent optical performance of the optical emitter over a predefined range of temperatures and to deviate from consistent optical performance utilizing a specified deviation methodology for temperatures outside the predefined range of temperatures; and
a memory coupled to the controller circuit and having stored therein temperature values and at least two control values for the emitter driver circuit for at least some temperature values, and the memory further having stored therein a value for controlling an optical emitter bias current and a value for controlling a current swing of the optical emitter in association with at least one of the temperature values;
wherein the controller circuit generates the control signals based at least in part on two of the control values that are associated with the same temperature value in the memory.
2. The optoelectronic apparatus of claim 1 , further comprising a temperature sensor to detect an approximate temperature of the optical emitter.
3. The optoelectronic apparatus of claim 1 , wherein the controller circuit generates the control signals based at least in part on the approximate temperature of the optical emitter.
4. The optoelectronic apparatus of claim 3 , wherein if the approximate temperature is higher than the predefined range of temperatures, the controller circuit provides control signals to the emitter driver circuit so as to decrease optical performance of the optical emitter in accordance with the specified deviation methodology.
5. The optoelectronic apparatus of claim 3 , wherein if the approximate temperature is lower than the predefined range of temperatures, the controller circuit provides control signals to the emitter driver circuit so as to increase optical performance of the optical emitter in accordance with the specified deviation methodology.
6. The optoelectronic apparatus of claim 1 , wherein the optical emitter comprises a laser.
7. The optoelectronic apparatus of claim 1 , wherein the controller circuit and the memory are portions of a single integrated circuit.
8. The optoelectronic apparatus of claim 1 , wherein the memory comprises a non-volatile memory.
9. An optoelectronic apparatus comprising:
an optical emitter;
an emitter driver circuit configured and arranged to drive the optical emitter;
a controller IC coupled to the emitter driver circuit, the controller IC being configured to:
provide control signals to the emitter driver circuit so as to facilitate, for a predefined range of temperatures, operation of the optical emitter at a target power output that is within a constant power region; and
provide control signals to the emitter driver circuit so as to facilitate, for temperatures outside the predefined range of temperatures, operation of the optical emitter at a target power output that is outside the constant power region, the control signals for operation outside the constant power region being based upon a specified deviation methodology; and
memory coupled to the controller IC and having stored therein temperature values and at least two control values for the emitter driver circuit for at least some temperature values, such that control signals generated by the controller IC are based at least in part on two of the control values that are associated with the same temperature value in the memory.
10. The optoelectronic apparatus as recited in claim 9 , wherein the deviation methodology specifies that the target power output outside the constant power region varies with respect to changes in temperature.
11. The optoelectronic apparatus as recited in claim 10 , wherein the deviation methodology specifies that at least some variations in the target power output outside the constant power region are one of: substantially linear with respect to changes in temperature; or, substantially non-linear with respect to changes in temperature.
12. The optoelectronic apparatus as recited in claim 9 , wherein the deviation methodology specifies that operation of the optoelectronic apparatus meets K min and I max limits for a range of temperatures that encompasses, and extends beyond, the predetermined range of temperatures.
13. The optoelectronic apparatus as recited in claim 9 , wherein the optical emitter comprises a VCSEL.
14. The optoelectronic apparatus as recited in claim 9 , wherein control signals provided by the controller IC are based at least in part on a temperature of the optical emitter.
15. The optoelectronic apparatus as recited in claim 9 , wherein the controller IC includes an I 2 C serial interface configured and arranged to permit communication between the optoelectronic apparatus and a host device.
16. The optoelectronic apparatus as recited in claim 9 , wherein:
the optical emitter comprises an element of a ROSA configured to communicate with the controller IC; and
the optoelectronic apparatus further comprises a TOSA configured to communicate with the controller IC.
17. The optoelectronic apparatus as recited in claim 9 , wherein the memory further has stored therein a value for controlling an optical emitter bias current and a value for controlling a current swing of the optical emitter in association with at least one of the temperature values.
18. The optoelectronic apparatus as recited in claim 9 , wherein the controller IC includes a temperature sensor in thermal communication with the optical emitter.
19. An optoelectronic apparatus comprising:
an optical emitter;
an emitter driver circuit configured and arranged to drive the optical emitter;
a controller IC coupled to the emitter driver circuit, the controller IC being configured to:
provide control signals to the emitter driver circuit so as to facilitate, for a predefined range of temperatures, operation of the optical emitter at a target power output that is within a constant power region; and
provide control signals to the emitter driver circuit so as to facilitate, for temperatures outside the predefined range of temperatures, operation of the optical emitter at a target power output that is outside the constant power region; and
memory coupled to the controller IC and having stored therein temperature values and control values, one or more control signals of the controller IC being based at least in part on one or more of the stored temperature values and control values.