Claims
- 1. A method of driving a laser in a passive optical network to determine a laser drive current corresponding to a logic 0 light intensity, the method comprising the steps of:
supplying a laser drive current sufficient to drive the laser at a predetermined light intensity greater than the logic 0 light intensity during a zero level measurement interval; measuring the laser drive current supplied; calculating from the measured laser drive current a 0 laser drive current, the calculated 0 laser drive current corresponds to the logic 0 light intensity; and using the calculated 0 laser drive current during transmission of data corresponding to a logic 0.
- 2. The method according to claim 1, wherein the predetermined light intensity is less than 15% light intensity.
- 3. The method according to claim 1, wherein the predetermined light intensity is less than 20% light intensity.
- 4. The method according to claim 1, wherein the predetermined light intensity is less than 75% light intensity.
- 5. The method according to claim 1, wherein the predetermined light intensity is 100% light intensity of less.
- 6. The method according to claim 1, further comprising the step of:
measuring a light intensity of the laser; and feeding back a control signal based on the measured light intensity of the laser; and regulating the supplied laser drive current based on the feed back control signal to maintain the laser at the predetermined light intensity.
- 7. The method according to claim 1, further comprising the step of:
pre-driving the laser with a calculated pre-drive laser current prior to receiving a transmission grant.
- 8. The method according to claim 7, wherein the calculated pre-drive laser current is less than the calculated 0 laser drive current and greater than 0 current.
- 9. The method according to claim 7, wherein the laser is pre-driven a predetermined amount of time prior to receiving the transmission grant.
- 10. The method according to claim 7, wherein the laser is pre-driven except during the transmission grant.
- 11. A laser drive, comprising:
a current source; a current measuring device connected to the current source capable of generating a current level signal based on the measured current; a processor adapted to receive the generated current level signal; and a memory, the current source supplies a laser drive current to drive a laser at a predetermined light intensity during a zero level measurement interval, the current measuring device measures the current from the current source and transmits the generated current level signal to the processor, the processor calculates a 0 laser drive current based on the predetermined light intensity and the measured current, the processor causes the calculated 0 laser drive current to be stored in memory, such that during transmission of data corresponding to a logic 0, the current source supplies the laser with the calculated 0 laser drive current.
- 12. The laser drive according to claim 11, wherein the current source comprises at least one of a DAC, a ASIC silicon, a microchip, and programmable logic.
- 13. The laser drive according to claim 11, wherein the current source is a field programmable gate array.
- 14. The laser drive according to claim 11, wherein the predetermined light intensity is less than one of 15%.
- 15. The laser drive according to claim 11, wherein the predetermined light intensity is less than 50%.
- 16. The laser drive according to claim 11, wherein the current source supplies a pre-drive current to the laser prior to receiving a transmission grant.
- 17. The laser drive according to claim 16, wherein the pre-drive current is less than the calculated 0 laser drive current.
- 18. The laser drive according to claim 11, comprising:
a light intensity measuring device, the light intensity measuring device provides a feed back signal to the processor such that the current source supplies current to maintain the predetermined light intensity.
- 19. The laser drive according to claim 18, wherein the light intensity measuring device is a photodiode.
- 20. A method of driving a laser in a passive optical network to pre-charge the laser, the method comprising the steps of:
storing a logic 0 current required to drive the laser at the logic 0; supplying a laser drive current sufficient to pre-drive the laser at a current less than the logic 0 current prior to receiving a transmission grant; receiving a transmission grant; and driving the laser to transmit information.
- 21. The method according to claim 20, wherein the supplying step comprises turning on and off output pins of a field programmable gate array.
- 22. The method according to claim 20, wherein
the supplying step comprises providing a measurement current to the laser during a zero level measurement interval, measuring the measurement current; and calculating the logic 0 current.
- 23. A laser drive, comprising:
means for supplying current to a laser; a current measuring device connected to the means for supplying current capable of generating a current level signal based on the measured current; a processor adapted to receiving the generated current level signal and causing the means for supplying current to output a laser drive current; and a memory, the memory stores a 0 intensity laser drive current, the 0 intensity laser drive current corresponds to a current greater than 0 amps that drives the laser at a zero light intensity, the processor causes the means for supplying current to output the laser drive current at a level below the 0 intensity laser drive current prior to the laser receiving a transmission grant.
- 24. The laser drive according to claim 23, wherein the means for supplying comprises a field programmable gate array having a plurality of pins connected in series to a plurality of resistors.
- 25. The laser drive according to claim 23, wherein
the means for supplying provides a measurement current to the laser during a zero level measurement interval, the measurement current drives the laser to output a predetermined light intensity greater than 0%, and the processor using the measurement current to calculate the 0 intensity laser drive current.
RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Patent Application Serial No. 60/382,506, filed May 21, 2002, titled METHODS AND APPARATUSES FOR OPTICAL NETWORK TERMINATION AND MEDIA ACCESS CONTROL IN A PASSIVE OPTICAL NETWORK. This application is a divisional application of U.S. Patent Application titled METHODS AND APPARATUSES FOR DIRECT DIGITAL DRIVE OF A LASER IN A PASSIVE OPTICAL NETWORK, filed Jul. 9, 2002, identified by Attorney Docket Number 40405.830029.001, incorporated herein by reference.
Provisional Applications (1)
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Number |
Date |
Country |
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60382506 |
May 2002 |
US |