GaAs MESFET laser-driver IC for 1.7-Gbit/s lightwave transmitter

GaAs monolithic integrated circuits for modulating junction lasers (laser drivers) have been developed for a 1.7-Gb/s lightwave communication system. The modulation currents can be varied continuously from a few mA up to 50 or 100 mA, depending on the types of laser drivers. It has been demonstrated that devices of the low-current type are capable of driving a 50- Omega load with a 50-mA modulation current with pulse rise and fall times (10% to 90%) less than 200 ps, and the high-current devices are capable of driving a 25- Omega load with up to 100-mA modulation current with pulse rise and fall times less than 250 ps. Nearly temperature-independent performance has been achieved from 0 degrees C to 70 degrees C. The laser drivers are also capable of providing output DC currents proportional to the duty cycle of input data for the purpose of duty-cycle-independent feedback control of junction lasers. The circuit designs and performance of these devices are described.<
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