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
DROP
PORTS
PORTS
OPTICAL
SWITCH
PHOTODIODES
11
12
ATTENUATOR
DWDM
IN
DWDM
OUT
ATTENUATOR
FIBRE
AWG FIBRE
AWG
1n–1
1n
ATTENUATOR
ATTENUATOR
TIA/LOG AMP
(AD8304/AD8305)
ADG731
(32:1 MUX)
N:1 MULTIPLEXER
AD5382,
32-CHANNEL,
14-BIT DAC
AD7671
(0-5V, 1MSPS)
CONTROLLER
16-BIT ADC
Figure 44. OADM Using the AD5382 as Part of an Optical Attenuator
Rev. 0 | Page 36 of 40
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