AKM Confidential
AK2571
= Preliminary =
AK2571
Single-Chip Automatic Power/Temperature Control
for WDM Laser Diodes
Features
Single Chip LSI that integrates APC (Auto Power Control) and ATC (Auto Temperature Control) functions for
WDM Laser Module
A controlling TEC (Thermal Electrical Cooler) stabilizes the temperature of LD module in the range of +/-0.1
°
C
by PID algorithm.
Parameters controlling Laser Diode are user programmable and stored in EEPROM
Internal Temperature Sensor detects on-chip temperature, enabling compensation internal and external
components that may be affected by changing ambient temperature.
Autonomous operation (internal oscillator and logic).
Pin-selectable wavelength data for tunable laser diodes (four options).
Single 3.3V operation
64-pin LQFP or Bare chip
Description
The AK2571 is a single-chip solution for WDM Laser Diode Module applications. It integrates both ATC (Auto
Temperature Control) and APC (Auto Power Control) functions in a small 64-pin LQFP or bare die package..
The ATC function of the AK2571 detects the LD module temperature via an external thermister and uses the PID
algorithm to control the Thermo-Electric Cooler (TEC). This provides +/- 0.1
°
C stabilization.. A customer can program the
appropriate PID parameters into the internal EEPROM , thereby providing compensation characteristics for each Laser
Diode. TEC control is handled through either PWM or Analog current control through I-DAC4. These are easily selected
by an EEPROM (Register) setting.
The APC has two functions. The first function is to compensate for Laser Diode power decreases caused by aging. The
other function is to compensate for temperature variations of AK2571 and external components (current amplifier or
driver circuits) which may be affected by ambient temperature within the LDM. The AK2571 does this by controlling
BIAS and modulation current according to the look up table in EEPROM .
The AK2571 has every alarm needed for WDM modules (Loss of power, Over current, Temperature etc.). There is a
dithering function for modulation current that improves the extinction ratio for long distance transmissions.
Also, parameter and compensation data can be stored for four wavelengths. If a customer uses a tunable laser diode, it is
very easy to change the wavelength by pin control.
<Rev. 0.6E Preliminary> -1-
2001/11
