Patent ID: 8081883
Filing Date: 2011-12-20
Classification: H01S,H04B

Abstract:
1. An apparatus for compensating for optical crosstalk in an optical output power feedback monitoring system of a parallel optical transmitter or transceiver, the apparatus comprising: n feedback control loops, where n is a number of optical transmit channels in the parallel optical transmitter or transceiver and is equal to or greater than 2, each feedback control loop having at least a laser diode driver circuit, a laser diode, coupling optics, and a photodiode, wherein the laser diode is modulated to produce an optical signal and wherein the coupling optics couple at least a portion of the optical signal produced by the laser diode onto the photodiode, the portion of the optical signal coupled onto the photodiode being an optical feedback signal, wherein the photodiode converts the optical feedback signal into an electrical feedback signal, the electrical feedback signal being input to a first terminal of the laser diode driver circuit; a memory device having n original reference values stored therein; and a controller configured to cause, when operating in a normal mode of operations, the n original reference values to be retrieved from the memory device and applied to respective second terminals of respective laser diode driver circuits of respective feedback control loops, wherein prior to causing the respective original reference values to be applied to the second terminals of the respective laser diode driver circuits, the controller determines whether or not adjustments need to be made to the original reference values to compensate for a change in an amount of optical crosstalk present in or absent from one or more of the feedback control loops, and wherein if the controller determines that adjustments need to be made, the controller adjusts the original reference values to produce new reference values and causes respective new reference values to be applied to the respective second terminals of the laser diode driver circuit.