Method and apparatus for controlling output power levels of a laser used for optical data transmission based on data rate-speed optical feedback

Abstract

High-speed measurements of the output power level of a laser are obtained by using a high-speed laser output power monitoring device that is capable of producing an electrical feedback signal having an amplitude that varies as the output power level of the laser varies. A high-speed amplitude detector receives the electrical feedback signal and detects the amplitude of the feedback signal and produces an optical modulation amplitude (OMA) detection signal. The OMA detection signal is received in a high-speed amplitude measurement device that measures the OMA and produces an OMA measurement value. The OMA measurement value is then processed by the laser controller to obtain a modulation current control signal, which is then output to the laser driver to cause the laser driver to adjust the laser modulation current to obtain a desired or optimum laser output power level. An average amplitude measurement value may also be obtained using an average amplitude measurement device that processes the OMA detection signal produced by the high-speed amplitude detector to obtain the average amplitude measurement value. The laser controller receives the average amplitude measurement value and processes it to obtain a bias current control signal, which is then output to the laser driver to cause it to adjust the amplitude of the bias current to obtain a desired or optimum average laser output power level.