Datasheet

AD5380 Data Sheet

Rev. C | Page 36 of 40

OPTICAL ATTENUATORS

Based on its high channel count, high resolution, monotonic

behavior, and high level of integration, the AD5380 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, transim-

pedance amplifier and ADC in a closed-loop control system.

The AD5380 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.

ATTENUATOR

AWG

FIBRE

DWDM

OUT

OPTICAL

SWITCH

1n–1

DWDM

AD5380,

40-CHANNEL,

14-BIT DAC

N:1 MULTIPLEXER

16-BIT ADCCONTROLLER

TIA/LOG AMP

(AD8304/AD8305)

ADG731

(40:1 MUX)

AD7671

(0V TO 5V, 1MSPS)

PHOTODIODES

ADD

PORTS

DROP

PORTS

03731-044

Figure 44. OADM Using the AD5380 as Part of an Optical Attenuator