The MAX3863 is designed for direct modulation of laser diodes at data rates up to 2.7Gbps. An automatic power-control (APC) loop is incorporated to maintain a constant average optical power. Modulation compensation is available to increase the modulation current in proportion to the bias current. The optical extinction ratio is then maintained over temperature and lifetime. The laser driver can modulate laser diodes at amplitudes up to 80mA. Typical (20% to 80%) edge speeds are 50ps. The MAX3863 can supply a bias current up to 100mA. External resistors can set the laser output levels.