Distributed Bragg feedback intensity modulator in Ti:LiNbO3

Kim, R.; Zhang, J.; Eknoyan, O.; Taylor, Henry F.; Smith, Thomas L.

doi:10.1049/el:20052450

Cited by 12 publications

(2 citation statements)

References 2 publications

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“…The potential of EO controlled PC structures has been investigated in the literature through simulations 15,16 and experi-mental demonstrations. [17][18][19] The future deployment of photonic technology largely rests on the tunability of PC characteristics.…”

Section: Introductionmentioning

confidence: 99%

Simultaneous characterization of the electro-optic, converse-piezoelectric, and electroabsorptive effects in epitaxial (Sr,Ba)Nb2O6 thin films

Cuniot-Ponsard

Desvignes

Bellemain

et al. 2011

Journal of Applied Physics

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Implementation of the linear electro-optic ͑EO͒ effect in thin film waveguides is expected to allow drastic reductions in the drive voltage, power, and dimensions of devices devoted to light modulation. It should also enable the realization of electrically tunable photonic crystal devices. In this paper we introduce a method which eliminates systematically the sources of the unreliability which strongly affects thin film EO characterization. Based on a Fabry-Perot reflective configuration, the method enables characterizing simultaneously the EO, converse-piezoelectric, and electroabsorptive effects in a film. It provides the magnitude and sign of each of the involved coefficients, and allows accounting for the whole of experimental data versus angle of incidence for both transverse-electric and transverse-magnetic polarizations. At = 633 nm and room temperature, the results obtained with an epitaxial strontium barium niobate ͑Sr x Ba 1−x Nb 2 O 6 , x = 0.60͒ ferroelectric thin film, are: r 13 = +8.5Ϯ 1.3 pm/ V, r 33 = +38.9Ϯ 0.5 pm/ V, d 33 = ⌬e / ⌬V =+21Ϯ 4 pm/ V, and ⌬k o / ⌬V = ͑+9.8Ϯ 0.6͒ ϫ 10 −6 , where r 13 and r 33 are two linear EO coefficients, d 33 is a converse-piezoelectric coefficient, and e, k o , V represent, respectively, the film thickness, film ordinary extinction coefficient, and applied voltage. Converse-piezoelectric and electroabsorptive effects are found significant in the film response at a frequency below piezoelectric resonance. Diagonal and effective EO coefficients of the ͑Sr, Ba͒Nb 2 O 6 ͑SBN͒ film explored in the present work are larger than those of a crystal of lithium niobate ͑LN͒ at the same wavelength = 633 nm. Taking into account the significant difference in dielectric permittivity between the two materials, advances and potential of LN and SBN thin film paths are compared.

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Section: Introductionmentioning

confidence: 99%

Simultaneous characterization of the electro-optic, converse-piezoelectric, and electroabsorptive effects in epitaxial (Sr,Ba)Nb2O6 thin films

Cuniot-Ponsard

Desvignes

Bellemain

et al. 2011

Journal of Applied Physics

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“…6,7 One-dimensional Bragg grating structures have been proposed for slow wave modulator devices using bulk LiNbO 3 crystal. 8,9 Lithium niobate crystals have already demonstrated slow light effects and enhancement of electrooptic coefficient by a factor more than 100 in a PhC waveguide. We have demonstrated one and two dimensional photonic crystal structures in thin film BTO waveguides and measured their optical transmission properties.…”

Section: Introductionmentioning

confidence: 99%

Ultrafast modulators based on nonlinear photonic crystal waveguides

Liu¹,

Li²,

Tu³

et al. 2011

SPIE Proceedings

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Nonlinear photonic crystal (PhC) waveguides are being developed for ultrafast modulators. To enable phase velocity matching we have investigated one-and two-dimensional structures. Photonic crystal (PhC) waveguides based on epitaxial barium titanate (BTO) thin film in a Si 3 N 4 /BTO/MgO multilayer structure were fabricated by electron beam lithography or focused ion beam (FIB) milling. For both one-and two-dimensional PhCs, simulation shows that sufficient refractive index contrast is achieved to form a stop band. For one-dimensional Bragg reflector, we measured its slow light properties and the group refractive index of optical wave. For a millimeter long waveguide a 27 nm wide stop band was obtained at 1550 nm. A slowing of the light was observed, the group refractive indices at the mid band gap and at the band edges were estimated to be between 8.0 and 12 for the transverse electric (TE) mode, and 6.9 and 13 for the transverse magnetic (TM) mode. For TE optical modes, the enhancement factor of EO coefficient ranges from 7 to 13, and for the TM mode, the factor ranges from 5.9 to 15. Measurements indicate that near velocity phase matching can be realized. Upon realizing the phase velocity matching condition, devices with a small foot print with bandwidths at 490 GHz can be attained. Two-dimensional PhC crystal with a hexagonal lattice was also investigated. The PhCs were fabricated from epitaxial BTO thin film multilayers using focused ion beam milling. The PhCs are based on BTO slab waveguide and air hole arrays defined within Si 3 N 4 and BTO thin films. A refractive index contrast of 0.4 between the barium titanate thin film multilayers and the air holes enables strong light confinement. For the TE optical mode, the hexagonal photonic crystal lattice with a diameter of 155 nm and a l a t t i c e c o n s t a n t o f 7 4 0 nm y i e l d s a photonic bandgap over the wavelength range from 1525 to 1575 nm. The transmission spectrum of the PhC waveguide exhibits stronger Fabry Perot resonance compared to that of conventional waveguide. Measured transmission spectra show a bandgap in the ΓM direction in the reciprocal lattice that is in agreement with the simulated results using the finitedifference time-domain (FDTD) method. Compared to polarization intensity EO modulator with a half-wave voltage length product of 4.7 V·mm. The PhC based EO modulator has a factor of 6.6 improvement in the figure of merit performance. The thin film PhC waveguide devices show considerable potential for ultra-wide bandwidth electro-optic modulators as well as tunable optical filters and switches.

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