Tracking modulation limiter for lasers

摘要

A tracking modulation limiter for laser diodes tracks from the output of a laser diode the maximum forward current. The maximum forward current is multiplied by a factor less than one to generate a control current representative of the maximum negative modulation for the laser diode. The control current is modulated by an input modulation signal and combined with the maximum forward current to drive the laser diode so that the drive current does not fall below threshold.