APPLICATIONS
LASER DIODE DRIVER (LDD) CALIBRATION
The ADN2860 can be used with any laser diode driver. Its high
resolution, compact footprint, and superior temperature drift
characteristics make it ideal for optical parameter setting.
The ADN2841 is a 2.7 Gbps laser diode driver that uses a
unique control algorithm to manage both the laser average
power and extinction ratio after initial factory calibration. It
stabilizes the laser data transmission by continuously monitoring
its optical power and by correcting the variations caused by
temperature and the laser degradation over time. In the
ADN2841, the IMPD monitors the laser diode current. Through
its dual-loop power and extinction ratio control, calibrated by
the ADN2860, the internal driver controls the bias current, IBIAS,
and, consequently, the average power. It also regulates the
modulation current, IMODP, by changing the modulation current
linearly with slope efficiency. Any changes in the laser threshold
ADN2860
current or slope efficiency are, therefore, compensated. As a
result, this optical supervisory system minimizes the laser
characterization efforts, enabling designers to apply comparable
lasers from multiple sources.
VCC VCC
ADN2860
SDA
SCL
ADN2841
PSET
ERSET
ASET
Figure 33. Optical Supervisory System
Rev. A | Page 19 of 20