AK2572 pdf datasheet (APC for

The AK2572 enables to keep the optical power of the direct
modulation LD (Laser Diode) constant by the APC
(Automatic Power Control) circuit. It consists of a current
programming function (APC_FF) responding to the
temperature characteristics of each LD, and a Digital
feedback function (APC_FB) to adjust the LD current
based on the monitoring PD (Photo Diode) current.
The AK2572 is also applicable to the Burst mode
transmission. The device equips a Power leveling function
to switch a temperature compensation programming data
by either Hardware pin control or Register setting.
The On-chip EEPROM (Non-volatile memory) allows to
adjust and to keep the individual setting data for each LD
characteristics via 2-wire Digital interface after being
assembled into sub-system. As 1k bits User Area is
allocated in the EEPROM, which supports the ID field of
the SFP specification, a proper operation required for the
SFP module is realized by using the TXFAULT function.