METHOD AND DEVICE FOR COMPENSATING OPTICAL CROSSTALK OF OPTICAL OUTPUT POWER FEEDBACK MONITORING SYSTEM OF PARALLEL OPTICAL TRANSMITTER

摘要

PROBLEM TO BE SOLVED: To compensate fluctuation in optical crosstalk in an optical output power monitoring system, which is caused by enabling and/or disabling a laser.

SOLUTION: A photodiode 136 for a monitor converts a part 142 of a received optical data signal 138 into an analog electric signal 143. An ADC 137 converts this analog electric signal into a digital value 144 of plural bits. This digital value is fed back to a closed-loop control circuit 133. A laser diode driving circuit compares the digital value with a preselected digital reference value 150 and generates a driving signal 156. This driving signal drives a current source 134. This current source varies a bias current of a laser diode 135, thereby substantially stabilizing the average output power level of the laser diode.

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