AD5382
OPTICAL ATTENUATORS
Based on its high channel count, high resolution, monotonic
behavior, and high level of integration, the AD5382 is ideally
targeted at optical attenuation applications used in dynamic
gain equalizers, variable optical attenuators (VOA), and optical
add-drop multiplexers (OADM). In these applications, each
wavelength is individually extracted using an arrayed wave
guide; its power is monitored using a photodiode, transimped-
ance amplifier and ADC in a closed-loop control system. The
AD5382 controls the optical attenuator for each wavelength,
ensuring that the power is equalized in all wavelengths before
being multiplexed onto the fiber. This prevents information loss
and saturation from occurring at amplification stages further
along the fiber.
ADD
PORTS
OPTICAL
SWITCH
11
12
DROP
PORTS
PHOTODIODES
ATTENUATOR
ATTENUATOR
DWDM
OUT
AWG FIBRE
DWDM
IN
FIBRE AWG
1n–1
1n
ATTENUATOR
ATTENUATOR
TIA/LOG AMP
(AD8304/AD8305)
AD5382,
32-CHANNEL,
14-BIT DAC
CONTROLLER
N:1 MULTIPLEXER
ADG731
(32:1 MUX)
16-BIT ADC
AD7671
(0-5V, 1MSPS)
Figure 44. OADM Using the AD5382 as Part of an Optical Attenuator
Rev. 0 | Page 36 of 40
03733-0-013
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