Method and apparatus for controlling laser modulation based on measurements of average laser output power

A method for controlling modulation of a laser comprising:

• monitoring optical feedback from a laser to obtain a measurement of an average output power level of the laser;
• determining whether the measured average output power level of the laser is above or below a target average output power level;
• if a determination is made that the measured average output power level is above or below the target average output power level, adjusting an amplitude of an electrical bias current being delivered to the laser until the measured average output power level of the laser is at least substantially equal to the target average output power level;
• determining whether the laser is being over-modulated or under-modulated;
• and
• if a determination is made that the laser is being over-modulated or under-modulated, adjusting the amplitude of an electrical modulation current being delivered to the laser to reduce or eliminate over-modulation or under-modulation of the laser.

A computer program for controlling modulation of a laser, the computer program comprising instructions stored on a computer-readable medium, the instructions comprising:

• instructions for obtaining a measurement of an average output power level of a laser based on monitored optical feedback from the laser;
• instructions for determining whether the measured average output power level of the laser is above or below a target average output power level;
• instructions for generating a control signal that causes an amplitude of an electrical bias current being delivered to the laser to be adjusted if it is determined that the measured average output power level is above or below the target average output power level, the amplitude of the electrical modulation current being adjusted until the measured average output power level of the laser is at least substantially equal to the target average output power level;
• instructions for determining whether the laser is being over-modulated or under-modulated;
• and
• instructions for generating a control signal that causes the amplitude of an electrical modulation current being delivered to the laser to be adjusted if it is determined that the laser is being over-modulated or under-modulated.