Patent ID: 7054564

Claim:
An open-loop thermal compensation circuit for use in a burst-mode optical transmitter, the open-loop thermal compensation circuit comprising: a laser diode for converting an electrical signal to an optical signal, the laser diode having an optimum optical power level, wherein the optical power level drifts over any temperature fluctuation; and a thermal reference circuit for supplying a thermal current I TH in accordance with a surrounding temperature for adjusting the drifted optical power level, wherein when the thermal current increases, the adjusted optical power level increases, and wherein when the thermal current decreases, the adjusted optical power level decreases; a voltage control circuit for providing a control current I CNTL for turning the laser diode on when the burst-mode optical transmitter detects an incoming electrical signal, wherein the burst-mode optical transmitter provides an indication signal that the electrical signal is present, and wherein the voltage control circuit turns the laser diode off in the absence of the electrical signal; adding means for adding the thermal current I TH and the control current I CNTL to provide a summing current I A , wherein the summing current I A is provided as a summing voltage V A ; an operational amplifier for receiving the summing voltage V A and for adjusting the summing voltage to equal a reference voltage V ref , wherein the adjusted summing voltage provides an adjusted summing current; and a voltage converter for converting the adjusted summing current to a laser voltage V B , wherein the laser voltage V B adjusts a laser current I laser , and wherein the laser current I laser is a function of the optical power level, whereby the thermal reference circuit ensures that the optical power level remains at the optimum power level.