What is AWG | Arrayed Waveguide Grating Optical MUX DEMUX

This page describes basics of AWG (Arrayed Waveguide Grating) used in Optical fiber. It mentions operation of Arrayed Waveguide Grating(AWG) as optical MUX and DEMUX. The features or characteristics of Optical Arrayed Waveguide Grating are mentioned.

AWG works on principle of interferometry. It is widely used as optical multiplexer and optical demultiplexer.

Operation or function of AWG

Arrayed Waveguide Grating based Optical MUX DEMUX

Let us understand operation of AWG as optical demultiplexer:

• Step-1: As shown incoming light signal having all wavelengths (λ-1,λ-2,.....,λ-n) are fed using optical fiber(F) into input cavity or input coupler (designated as 'S1') part of the optical AWG (Arrayed Waveguide Grating).

• Step-2: This multiplexed signal is passed through the free space portion of 'S1'.

• Step-3: Next, light gets divided into array of waveguides. Here phase delay proportional to wavelength is introduced to optical signals passed from different waveguides of different lengths.

• Step-4: Now these phase delayed signals are made to pass from output cavity or output coupler (designated as 'S2') . This cavity is connected with multiple optical fiber cables. At this stage, light signals after passing through different lengths of waveguides will interfere with one another. As a result, each output optical fibers are fed with one unique wavelength of light having maximum amplitude.

• Step-5: At this stage, with the use of multiple optical fiber cables different wavelengths of light are taken as output.

For AWG to be used as optical multiplexer reverse operations of the steps mentioned above will take place. Here individual light signals having different wavelengths are provided as input at location ⑤ of AWG and multiplexed output is derived from location ① of AWG(Arrayed Waveguide Grating).

Features or characteristics of Optical Arrayed Waveguide Grating

Following are the features of Optical Arrayed Waveguide Grating:

• As mentioned above it is used as optical multiplexer. This application is used in DWDM network to multiplex various WDM channels into one fiber cable.

• They are used as optical de-multiplexers at receiver end of DWDM network.

• AWGs are used in OADM which is part of long haul fiber optic communication system.

• They are used in FTTx optical systems for example as CWDM MUX and DEMUX.

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