An integrated laser diode driver (LDD) driving an edge-emitting laser diode was designed and fabricated by 0.35 μm BiCMOS
technology. This paper proposes a scheme which combines the automatic power control loop and temperature compensation for
modulation current in order to maintain constant extinction ratio and average optical power. To implement temperature compensation
for modulation current, a novel circuit which generates a PTAT current by using the injecting base current of a bipolar transistor
in saturation region, and alternates the amplifier feedback loop (closed or not) to control the state of the current path
is presented. Simulation results showed that programmed by choice of external resistors, the IC can provide modulation current
from 5 mA to 85 mA with temperature compensation adjustments and independent bias current from 4 mA to 100 mA. Optical test
results showed that clear eye-diagrams can be obtained at 155 Mbps, with the output optical power being nearly constant, and
the variation of extinction ratio being lower than 0.7 dB.
Key words Laser diode driver (LDD) - Automatic power control (APC) - Extinction ratio - Temperature compensation
CLC number TN242
Project (No. 2006AA01Z226) supported by the Hi-Tech Research and Development Program (863) of China