FOA2322A Datasheet, PDF (22/37 Pages) Infineon Technologies AG – 3.2 Gbi t /s Laser Driver IC for Telecom and Datacom Applications

FOA2322A
Electrical Characteristics
2.5
Principle of Modulation Current Control by Using a Pilot Signal
(Mode 2)
The DC-part of the monitor current controls the bias current. The difference of the optical
low frequency AC-part ∆Ppp is used for the modulation current control. ∆Ppp is
measured over the monitor current. The aim of the control is to settle ∆Ppp to Zero. (That
means a part of the pilot current amplitude on bias current is modulated below laser
current threshold. Therefore please take into account the laser characteristics, e.g.
switch-on delay, for higher data rates.) Mode 2 can only be used for DC-coupled laser
diodes.
P_Opt
P1
∆P1
P
∆Ppp
P0
∆P0
Figure 8
ab_PILOT
∆Ppp = ∆P0 - ∆P1
am_PILOT
I_Laser
ITD11333
Modulation Current Control by Using a Pilot Signal
Preliminary Data Sheet
18
2001-05