ARRAYED WAVEGUIDE GRATINGS

-By Shodhan Shetty

ECE-E641

Operation Principle

Free Propagation Regions (FPRs)

Arrayed Waveguides

AWG is a complex optical circuit contained on a glass-silicon wafer about 1 or 2 inches in diameter

Operation Principle (contd ..)

Application of Fresnel-Kirchoff diffraction integral to one of the FPRs in an AWG

WR

A( )

Operation Principle (contd..)

Fresnel-Kirchoff diffraction integral

Free Spectral Range

x

x

R

nxj

dAR

jxU e

2,

N eff

cFSR l.

2

l =Optical path length difference between adjacent array arms

Here,

Functions

WDM de(multiplexing) [1] OADM [2] Wavelength Routing Signal Processing Dispersion Compensation [3] Optical True-time delay lines [4] Optical Filters [5] Femto-second pulse train generation [6]

Specifications required: Channel Spacing Pass band Shape Adjacent Channel Crosstalk Free Spectral Range

WDM de(multiplexing) and OADM

Optical Filter [7]

Optical Filter (contd.. )

Optical Delay Line [4]

Here, d is distance betweenAntenna Array elements

AWG Chip

Bare AWG chipA packaged Arrayed waveguideGrating optical mux/demux module

References

[1] H. Yamada et al, "Measurement of Phase and Amplitude Error Distributions in Arrayed-Waveguide Grating Multi/Demultiplexers Based on Dispersive

Waveguide", Journal of Lightwave Technol., p.1309 (2000)[2] Y. Tachikawa, Y. Inoue, M.Kawachi, H. Takahashi, and K. Inoue,”Arrayed-

waveguide grating add-drop multiplexer with loop-back optical paths,” Electron. Lett., 1993,29,pp. 2133-2134

[3] Michael Parker, Stuart walker,” Arrayed waveguide gratings, fiber Bragg gratings, and photonic crystals: An Isomorphic Fourier transform light propagation analysis,” IEEE journal of selected topics in quantum electronics, vol. 8, pp. 1158, 2002

[4] B. Vidal et al, “Novel Dispersion-based optical delay line using Arrayed waveguide grating for antenna beamforming applications

[5] K. Okamoto,” Recent progress of integrated optics planar lightwave circuits,” Optical quantum Electron., vol. 31, pp. 107-129,1999

[6] D.E. Leird, A.M. Weiner et al, “Generation of high repetition rate WDM pulse trains from an Arrayed waveguide grating,” IEEE PTL, vol. 13, pp. 221, 2001

[7] Van Thourhaut et al,”Novel Geometry for an Integrated channel Selector,” IEEE Jour. of sel. Topics in Quantum Electronics