Patent ID: 6907055

Claim:
A method of controlling the optical modulation amplitude (OMA) of a laser diode, the method comprising the steps of: a) measuring the OMA of the laser diode, the measuring of the OMA comprising the steps of: i) applying a test signal to a bias current signal applied to the laser diode, the application of the test signal enabling two measurements of OMA to be effected, each OMA measurement being related to the slope of the laser diode operating region as measured at a position unique to that measurement, such that measurements are made at two positions, and ii) combining the two OMA measurement values so as to provide a measure of the overall laser diode OMA in the operating region, b) comparing the measured value of the OMA with a predetermined corresponding reference OMA value, and c) altering the modulation current to the laser diode in response to the measured OMA value not comparing favourably with the reference OMA value.