High-temperature operation of vertical cavity surface emitting lasers
Embodiments of the present invention provide a system for increasing an operational life of a VCSEL. The system can include control circuitry for reducing an amount of bias current at high temperatures and increasing a power of the laser at low temperatures. This control circuitry can further include at least one of a temperature sensor, a Field Programmable Gate Array, a read only memory module, and an electrically erasable programmable read only memory module (EEPROM). In alternate embodiments, the control circuitry can further include a lookup table that sets the bias current depending on a temperature of the laser. The laser can be part of an optoelectronic transceiver module which can include, by way of example and not limitation, SFP, XFP, X2, XAUI, XENPAK, XPAK, GBIC, 8G, 16G, and other optoelectronic modules.
1. A method for operating an optoelectronic transceiver having a vertical cavity surface emitting laser, the method comprising:
providing a plurality of bias current values, each of the bias current values corresponding to an operating environment temperature falling within a predefined temperature range, wherein:
the predefined temperature range comprises a first lower temperature range and a second higher temperature range; and
each of the bias current values corresponding to each of the operating environment temperatures in the second higher temperature range is constant; and
providing a bias current to the laser having a value that corresponds to the operating environment temperature.
2. A method according to claim 1 , wherein the method does not use average power control for providing the bias current to the vertical cavity surface emitting laser.
3. A method according to claim 1 , wherein the first lower temperature range includes between about a negative 10 degrees Celsius and a positive 65 degrees Celsius and the second higher temperature range includes temperatures higher than 65 degrees.
4. A method according to claim 3 , wherein the bias current values in the first lower temperature range increase at least 0.02 mA for every five degrees Celsius temperature increase.
5. A method according to claim 1 , further comprising a third temperature range even lower than the first lower temperature range.
6. A method according to claim 5 , wherein the bias current value associated with each temperature in the third temperature range increases with a decrease in temperature.
7. A method according to claim 6 , wherein the bias current value associated with each temperature in the third temperature range increases by at least 0.02 mA for each five degree decrease in associated temperature in the third temperature range.
8. A method according to claim 1 , wherein the optical power control of the vertical cavity surface emitting laser is different when the temperature of the vertical cavity surface emitting laser is operated at temperatures within the first lower temperature range then within the second higher temperature range.
9. A method for operating an optoelectronic transceiver having a vertical cavity surface emitting laser, the method comprising:
providing a plurality of bias current values, each of the bias current values corresponding to an operating environment temperature falling within a predefined temperature range, wherein;
the predefined temperature range comprises a first lower temperature range and a second higher temperature range;
each of the bias current values corresponding to each of the operating environment temperatures in the second higher temperature range is constant over the second higher temperature range; and
each of the bias current values corresponding to each of the operating environment temperatures in the first lower temperature range decrease with a corresponding increase in temperature; and
providing a bias current to the laser having a value that corresponds to the operating environment temperature.
10. A method according to claim 9 , further comprising a third temperature range between the first lower temperature range and the second higher temperature range.
11. A method according to claim 10 , wherein the bias current values corresponding to each of the operating environment temperatures in the third temperature range increase with a corresponding increase in temperature.
12. A method according to claim 11 , wherein the first lower temperature range includes temperatures below about minus 15 degrees Celsius, the third temperature range includes temperatures between about minus 10 degrees Celsius and about positive 65 degrees Celsius, and the second higher temperature range includes temperatures higher than 70 degrees Celsius.
13. A method according to claim 12 , wherein the first lower temperature range and corresponding bias current values include 6.5 mA at minus 30 degrees Celsius, 6.45 mA at minus 25 degrees Celsius, 6.4 mA at minus 20 degrees Celsius, and 6.35 mA at minus 15 degrees Celsius.
14. A method according to claim 12 , wherein the third temperature range and corresponding bias current values include 6.35 mA at minus 10 degrees Celsius, 6.4 mA at minus 5 degrees Celsius, 6.45 mA at minus 0 degrees Celsius, and 6.6 mA at positive 5 degrees Celsius.
15. A method according to claim 14 , wherein the third temperature range and corresponding bias current values further include 6.7 mA at positive 10 degrees Celsius, 6.8 mA at positive 15 degrees Celsius, 6.9 mA at positive 20 degrees Celsius, and 7 mA at positive 25 degrees Celsius.
16. A method according to claim 15 , wherein the third temperature range and corresponding bias current values further include 7.2 mA at positive 30 degrees Celsius, 7.4 mA at positive 35 degrees Celsius, 7.8 mA at positive 40 degrees Celsius, and 8.2 mA at positive 45 degrees Celsius.
17. A method according to claim 16 , wherein the third temperature range and corresponding bias current values further include 8.6 mA at positive 50 degrees Celsius, 9 mA at positive 55 degrees Celsius, 9.5 mA at positive 60 degrees Celsius, and 10 mA at positive 65 degrees Celsius.
18. A method according to claim 12 , wherein the second higher temperature range and corresponding bias current values include about 10.5 mA at positive 70, 75, 80, and 85 degrees Celsius.
19. A method according to claim 9 , wherein the method does not use average power control for providing the bias current to the vertical cavity surface emitting laser.
20. A method for operating an optoelectronic transceiver having a vertical cavity surface emitting laser, the method comprising:
providing a plurality of bias current values, each of the bias current values corresponding to an operating environment temperature falling within a predefined temperature range, wherein:
the predefined temperature range comprises a first lowest temperature range, a second middle temperature range, and a third higher temperature range;
each of the bias current values corresponding to each of the operating environment temperatures in the first lowest temperature range decreases with a corresponding increase in temperature;
each of the bias current values corresponding to each of the operating environment temperatures in the second middle temperature range increases with a corresponding increase in temperature; and
each of the bias current values corresponding to each of the operating environment temperatures in the third higher temperature range is the same with corresponding increase in temperature; and
providing a bias current to the laser having a value that corresponds to the operating environment temperature.