Photonic chip-based RF spectrum analyzer

Photonic-chip-based RF spectrum analyzer

Raphael BouskilaRaphael Bouskila

09/24/1309/24/13 R. BouskilaR. Bouskila 22

OutlineOutline IntroductionIntroduction WaveguideWaveguide RF spectrum analyzerRF spectrum analyzer ConclusionConclusion


IntroductionIntroduction


WaveguideWaveguide Amount of nonlinearity dependent on Amount of nonlinearity dependent on

intensity:intensity:

Fiber core diameter: ~8-10 Fiber core diameter: ~8-10 μμmm– Effective area: ~50-80 Effective area: ~50-80 μμmm22

2

eff

2 n

A

πγλ

=


WaveguideWaveguide Second problem: DispersionSecond problem: Dispersion

– N.B. N.B. DD = = DDWGWG + + DDmatmat


WaveguideWaveguide What to do?What to do?

Solution: Ridge (or rib) waveguideSolution: Ridge (or rib) waveguide


WaveguideWaveguide High nonlinearity High nonlinearity

achieved via extremely achieved via extremely high mode confinementhigh mode confinement– AAeffeff: 2.61 : 2.61 μμmm22

Low dispersion Low dispersion achieved by achieved by compensating compensating DDmatmat with with DDWGWG


WaveguideWaveguide When they say “wide bandwidth,” they When they say “wide bandwidth,” they

aren’t kidding:aren’t kidding:


RF spectrum analyzerRF spectrum analyzer Regular PSD:Regular PSD:

RF spectrum:RF spectrum:

Used to characterize sources and Used to characterize sources and components; provides information about components; provides information about distortions and nonidealitiesdistortions and nonidealities

2

( ) ( ) i tS E t e dtωω = ∫

22( ) ( ) i t

RFS E t e dtωω = ∫


RF spectrum analyzerRF spectrum analyzer Typically done using expensive Typically done using expensive

electronicselectronics All-optical method preferred!All-optical method preferred!


RF spectrum analyzerRF spectrum analyzer


ConclusionConclusion Advantages:Advantages:

– Ultrawide bandwidthUltrawide bandwidth– Record-setting nonlinearityRecord-setting nonlinearity– Low dispersionLow dispersion

Limitations:Limitations:– Material and fabrication costsMaterial and fabrication costs– Dispersion could be minimized furtherDispersion could be minimized further


ReferencesReferences [1] M. Pelusi [1] M. Pelusi et al.et al. Photonic-chip-based radio- Photonic-chip-based radio-

frequency spectrum analyser with terahertz frequency spectrum analyser with terahertz bandwidth. bandwidth. Nature PhotonicsNature Photonics 33 , 139-143 (March , 139-143 (March 2009).2009).

[2] B. E. A. Saleh & M. C. Teich. Fundamentals [2] B. E. A. Saleh & M. C. Teich. Fundamentals of Photonics, 2nd ed. Wiley, 2007.of Photonics, 2nd ed. Wiley, 2007.

[3] G. P. Agrawal. Nonlinear Fibre Optics, 4th [3] G. P. Agrawal. Nonlinear Fibre Optics, 4th ed. Academic Press, 2006.ed. Academic Press, 2006.

[4] M. R. E. Lamont [4] M. R. E. Lamont et al. et al. Dispersion engineering Dispersion engineering of highly nonlinear As2S3 waveguides for of highly nonlinear As2S3 waveguides for parametric gain and wavelength conversion. parametric gain and wavelength conversion. Opt. ExpressOpt. Express 1515 , 9458–9463 (2007)., 9458–9463 (2007).

Photonic chip-based RF spectrum analyzer

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