Photonic Crystal Heterostructure Devices for WDM

James E. Toney

Battelle

505 King Ave.

Columbus, OH 43081

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Photonic Crystal Heterostructure Devices

Combine photonic crystal regions of different band structure to form resonant tunneling structures

Structures can be arranged to form filters, modulators, wavelength demultiplexers and optical switches

Avoid the use of difficult-to-fabricate line and point defects

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Photonic Crystal Slab Devices

Confine wave to a thin slab waveguide

Very thin layer (<0.5 mm) and high refractive index (~3) needed to achieve an omnidirectional band gap

Directional stop bands can be achieved with thicker layers and lower-index materials

Cross section through WG end

Cross section through air holes

1 mm

SiO2

Si

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Photonic Crystal Dual-Barrier Resonant Tunneling Structure

non-barrier regions

R=0.20a

barrier regions

R=0.40a

Optical “Potential”

Resonant

Tunneling

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Finite-Difference Time Domain Simulations of DBRT Structure

Resonant Wavelength Non-Resonant Wavelength

Same structure can be used for electro-optical modulation if

strong enough EO effect can be achieved.

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Transmission Spectrum of DBRT Filter

Peak 1.52 mm

FWHM 20 nm SOI/air

Thickness = 1 mm

a=0.42 mm

R1=0.35a

R2=0.40a

TM polarization

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Transmission Peak of DBRT Filter can be Tuned by Varying Hole Diameter

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Transmission Spectra of DBRT Filters in Low-Index Materials

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Coarse Wavelength Demultiplexer Based on DBRT Structures

l1 l2

l1, l2

barrier regions

R=R0

R=R1

R=R2

High loss limits the usefulness of the structure to a small number

of outputs.

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FDTD Simulations of 1x2 Demultiplexer (n=2.0)

l=1407 nm l=1480 nm

Same structure can be used for electro-optical switching if strong

enough EO effect can be achieved.

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SEM of Silicon-on-Insulator DBRT Structure

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Effect of Finite Lithographic Resolution on Transmission Spectrum of DBRT Filter

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Summary

Dual-barrier heterostructure is an alternative to photonic crystal slab devices based on line and point defects

Can be implemented in lower-index materials and thicker layers than PC slab waveguides

Structure is suitable for coarse WDM and EO modulators/switches

High fabrication quality is needed

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Acknowledgements

Dr. Sajeev John (University of Toronto)

Dr. Phillip Fauchet et al. (University of Rochester)

Cornell Nanofabrication Facility