AD5255 datasheet(19/20 Pages) AD

19 / 20 page

AD5255

Rev. 0 | Page 19 of 20

APPLICATIONS

LASER DIODE DRIVER (LDD) CALIBRATION

The AD5255 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 AD5255, 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 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.

AD5255

ADN2841

SDA

SCL

PSET

ERSET

ASET

VCC

Figure 33. Optical Supervisory System

AD5255 Datasheet(PDF) 19 Page - Analog Devices