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Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 18, Iss. 11 — May. 24, 2010
  • pp: 11192–11201
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Compact silicon photonic waveguide modulator based on the vanadium dioxide metal-insulator phase transition

Ryan M. Briggs, Imogen M. Pryce, and Harry A. Atwater  »View Author Affiliations


Optics Express, Vol. 18, Issue 11, pp. 11192-11201 (2010)
http://dx.doi.org/10.1364/OE.18.011192


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Abstract

We have integrated lithographically patterned VO2 thin films grown by pulsed laser deposition with silicon-on-insulator photonic waveguides to demonstrate a compact in-line absorption modulator for use in photonic circuits. Using single-mode waveguides at λ = 1550 nm, we show optical modulation of the guided transverse-electric mode of more than 6.5 dB with 2 dB insertion loss over a 2-µm active device length. Loss is determined for devices fabricated on waveguide ring resonators by measuring the resonator spectral response, and a sharp decrease in resonator quality factor is observed above 70 °C, consistent with switching of VO2 to its metallic phase. A computational study of device geometry is also presented, and we show that it is possible to more than double the modulation depth with modified device structures.

© 2010 OSA

1. Introduction

The thermochromic phase transition of crystalline VO2 occurring near 68 °C [1

1. F. J. Morin, “Oxides which show a metal-to-insulator transition at the Neel temperature,” Phys. Rev. Lett. 3(1), 34–36 (1959). [CrossRef]

] has been of interest in recent years for its potential applications in active optical devices. Monophase VO2 can be transformed from a relatively transparent insulating state with monoclinic crystal structure to a metallic rutile phase upon application of thermal [2

2. J. B. Goodenough, “The two components of crystallographic transition in VO2,” J. Solid State Chem. 3(4), 490–500 (1971). [CrossRef]

], optical [3

3. A. Cavalleri, C. Tóth, C. W. Siders, J. A. Squier, F. Ráksi, P. Forget, and J. C. Kieffer, “Femtosecond structural dynamics in VO2 during an ultrafast solid-solid phase transition,” Phys. Rev. Lett. 87(23), 237401 (2001). [CrossRef] [PubMed]

,4

4. H. T. Kim, Y. W. Lee, B. J. Kim, B. G. Chae, S. J. Yun, K. Y. Kang, K. J. Han, K. J. Yee, and Y. S. Lim, “Monoclinic and correlated metal phase in VO(2) as evidence of the Mott transition: coherent phonon analysis,” Phys. Rev. Lett. 97(26), 266401 (2006). [CrossRef]

], or electrical [5

5. B. G. Chae, H. T. Kim, D. H. Youn, and K. Y. Kang, “Abrupt metal–insulator transition observed in VO2 thin films induced by a switching voltage pulse,” Physica B 369(1-4), 76–80 (2005). [CrossRef]

,6

6. C. Ko and S. Ramanathan, “Observation of electric field-assisted phase transition in thin film vanadium oxide in a metal-oxide-semiconductor device geometry,” Appl. Phys. Lett. 93(25), 252101 (2008). [CrossRef]

] stimuli. The phase transition has been reported to occur on a time scale of 10−8 s under an applied electric field or by direct heating [5

5. B. G. Chae, H. T. Kim, D. H. Youn, and K. Y. Kang, “Abrupt metal–insulator transition observed in VO2 thin films induced by a switching voltage pulse,” Physica B 369(1-4), 76–80 (2005). [CrossRef]

,7

7. S. Chen, X. Yi, H. Ma, H. Wang, X. Tao, M. Chen, and C. Ke, “A novel structural VO2 micro-optical switch,” Opt. Quantum Electron. 35(15), 1351–1355 (2003). [CrossRef]

] and down to 10−13 s using ultrafast optical pumping [3

3. A. Cavalleri, C. Tóth, C. W. Siders, J. A. Squier, F. Ráksi, P. Forget, and J. C. Kieffer, “Femtosecond structural dynamics in VO2 during an ultrafast solid-solid phase transition,” Phys. Rev. Lett. 87(23), 237401 (2001). [CrossRef] [PubMed]

]. Furthermore, recent evidence suggests that the change in electronic properties can be induced independent of a structural transition [4

4. H. T. Kim, Y. W. Lee, B. J. Kim, B. G. Chae, S. J. Yun, K. Y. Kang, K. J. Han, K. J. Yee, and Y. S. Lim, “Monoclinic and correlated metal phase in VO(2) as evidence of the Mott transition: coherent phonon analysis,” Phys. Rev. Lett. 97(26), 266401 (2006). [CrossRef]

,5

5. B. G. Chae, H. T. Kim, D. H. Youn, and K. Y. Kang, “Abrupt metal–insulator transition observed in VO2 thin films induced by a switching voltage pulse,” Physica B 369(1-4), 76–80 (2005). [CrossRef]

], explaining the surprisingly short switching times observed by optical pumping, and suggesting that similarly short transitions might be achieved using an externally gated electric field. When switched by direct thermal stimulus, the rate of switching back to the insulating phase can be quite slow and depends on the thermal properties of a particular device; however, optically and electrically switched VO2 films have been reported to regain their insulating-phase properties over time scales on the order of 10−8 s [3

3. A. Cavalleri, C. Tóth, C. W. Siders, J. A. Squier, F. Ráksi, P. Forget, and J. C. Kieffer, “Femtosecond structural dynamics in VO2 during an ultrafast solid-solid phase transition,” Phys. Rev. Lett. 87(23), 237401 (2001). [CrossRef] [PubMed]

,5

5. B. G. Chae, H. T. Kim, D. H. Youn, and K. Y. Kang, “Abrupt metal–insulator transition observed in VO2 thin films induced by a switching voltage pulse,” Physica B 369(1-4), 76–80 (2005). [CrossRef]

]. To date, there have been demonstrations of VO2-based free-space optical modulators at infrared [7

7. S. Chen, X. Yi, H. Ma, H. Wang, X. Tao, M. Chen, and C. Ke, “A novel structural VO2 micro-optical switch,” Opt. Quantum Electron. 35(15), 1351–1355 (2003). [CrossRef]

] and visible [8

8. L. Jiang and W. N. Carr, “Design, fabrication and testing of a micromachined thermo-optical light modulator based on a vanadium dioxide array,” J. Micromech. Microeng. 14(7), 833–840 (2004). [CrossRef]

] wavelengths, where local heating was employed to induce the VO2 phase transition. While these studies show promising results, many of the potential applications of a modulator operating at telecommunications wavelengths require compact integration of waveguide-coupled devices on a Si chip.

Future scalable optical modulator designs are expected to operate with switching energies on the order of 10-15 J. For small volumes and short time scales, the thermal energy density required to induce the VO2 phase transition in a thermally isolated device is approximately c p ρΔT, where c p = 690 J/(kg K) is the heat capacity of insulating VO2, ρ = 4.3×10-3 kg/cm3 is the material density, and ΔT is the required temperature increase [13,14]. For a device initially at room temperature, this energy density is ~102 J/cm3, and a typical thin film device with a thickness of less than 100 nm and a footprint of 1 µm2 will have a switching energy on the order of 10-11 J. In comparison, for electrically driven VO2 devices with switching times on the order of 10-8 s, the field required to induce the VO2 phase transition has been reported to be ~105 V/cm [6], and the leakage current at the transition is ~104 A/cm2 [5,13]. The corresponding switching energy for the previously mentioned device geometry is 10-12 J, indicating that athermal switching can potentially be more efficient than thermal switching. To achieve even lower switching energies, it is feasible to envision device designs that, for example, further decrease the required volume of VO2 or reduce the leakage current through a VO2 film while still achieving the critical electric field required for the phase transformation.

2. Device fabrication

The waveguide pattern was transferred into the SOI to a depth of 40 nm using a C4F8/O2 plasma etching process in an Oxford Instruments ICP 380 system. The resist was removed along with residual polymer etch products in a 3:1 Piranha solution of H2SO4 and 30% H2O2 at 100 °C. After cleaning in buffered HF, the resonators were characterized using a fiber-coupled New Focus 6428 Vidia Swept tunable diode laser in order to obtain a baseline measurement of the ring resonator quality factor. Light was delivered to and extracted from the gratings using lensed fiber focusers, and waveguide modes of different polarization were accessed selectively by setting the input polarization and the coupling angle, as described in Ref. 16

16. R. M. Briggs, M. Shearn, A. Scherer, and H. A. Atwater, “Wafer-bonded single-crystal silicon slot waveguides and ring resonators,” Appl. Phys. Lett. 94(2), 021106 (2009). [CrossRef]

. Through-port transmission was measured with a fiber-coupled InGaAs photoreceiver that has nearly uniform response across the wavelength range of interest in this work.

After optical characterization, the native oxide was removed from the waveguides with another HF dip, and samples were immediately inserted into a vacuum chamber for pulsed-laser deposition of VO2. Samples were heated to 500 °C, and deposition was performed by ablating a vanadium metal target with 300-mJ pulses from an excimer laser at a rate of 10 Hz in 12 mTorr O2. For the devices considered here, VO2 layers were deposited to an average thickness of 65 nm, which was verified by atomic force microscopy (AFM). To pattern the VO2 tabs, waveguide samples were again coated with resist, and tabs were patterned by electron beam lithography. The pattern was transferred into the VO2 using Cr etchant (dilute (NH4)2Ce(NO3)6 and HClO4), and the resist was removed in acetone. All VO2 was removed from control resonators, which were tested again in the coupling setup described above to verify that resonator quality factor was not impacted by VO2 deposition and etching.

3. VO2 characterization

In order to characterize the VO2 on the SOI test bed structures, thin films were deposited simultaneously on high-resistivity Si(001) substrates and analyzed by multiple-angle spectroscopic ellipsometry in the near-infrared and X-ray diffractometry (XRD). Figure 2(a)
Fig. 2 (a) Real, n, and imaginary, k, parts of the index of refraction of a 65 nm-thick VO2 film on Si measured by multiple-angle spectroscopic ellipsometry across the near infrared spectrum. (b) X-ray diffraction spectrum of the same polycrystalline VO2 film (scanning electron micrograph shown in inset). (c) Electrical resistivity versus temperature of a 65 nm-thick VO2 film on SOI measured using the four-point van der Pauw method.
shows the real and imaginary parts of the index of refraction, n and k, of a 65-nm VO2 film, as extracted from the ellipsometry amplitude and polarization parameters, Ψ and Δ. Three sets of Ψ and Δ spectra were collected at reflection angles of 60°, 65°, and 70° from the surface normal. To obtain the complex index, the VO2 film was modeled as a dispersionless but lossy material over a wavelength window of 50 nm. With the thickness fixed at the value measured by AFM, the values of n and k were adjusted by a minimization algorithm to achieve the smallest error between the modeled and measured values of Ψ and Δ at all three angles simultaneously. The fitting process was repeated as the 50-nm wavelength window was moved along the measured spectrum in increments of 10 nm. The resulting discrete n and k values are plotted in Fig. 2(a) along with the polynomial fits used in the simulations described in Section 5. This interval fitting method functions as a running average filter to reduce noise in the extracted index values, and it allows for material dispersion to be determined without a phenomenological model of the material’s optical properties. The method is acceptable for both phases of VO2 in the near infrared since the index varies slowly with wavelength.

At 1550 nm, the index of VO2 is 3.21 + 0.17i near room temperature and 2.15 + 2.79i when heated to 100 °C, which indicates a clear transition from a nearly transparent state to a phase with metallic optical properties. In particular, the more than 16-fold increase in absorption is the basis for our optical modulator. Also, the optical properties for each phase are nearly constant over the telecommunications C-band (1530 to 1565 nm), making VO2 a suitable material for broadband devices.

Finally, we measured the electrical resistivity of the VO2 film on a small chip of SOI using the four-point van der Pauw method [18

18. L. J. van der Pauw, “A new method of measuring the resistivity and Hall coefficients on lamellae of arbitrary shape,” Philips Tech. Rev. 20, 220–224 (1958).

]. The temperature was changed in increments of 1 °C at a rate of less than 1 °C/min, and the resistivity was measured for all the various source-probe configurations possible with four symmetric points. At each temperature, all resistivity measurements agreed to within 5%, and the averaged values of resistivity are plotted in Fig. 2(c). Near room temperature, the measured resistivity is nearly equal to that of the top Si layer alone, indicating that the VO2 is not significantly more conductive than lightly doped Si; however, upon heating above 70 °C, we observe an abrupt transition to the much more conductive metallic phase. Upon cooling, the film regains its insulating-phase properties, but with a much less abrupt transition with respect to temperature. In particular, the VO2 does not completely switch back to its insulating phase until it has cooled to nearly 40 °C. This broad hysteresis is expected for films with the microstructure observed here, as previously reported by Suh, et al. [17

17. J. Y. Suh, R. Lopez, L. C. Feldman, and R. F. Haglund Jr., “Semiconductor to metal phase transition in the nucleation and growth of VO2 nanoparticles and thin films,” J. Appl. Phys. 96(2), 1209–1213 (2004). [CrossRef]

].

4. Modulator performance

As a baseline reference, the through-port transmission for a bare 400 µm-diameter ring resonator from which all VO2 was removed is shown in Fig. 3(a)
Fig. 3 (a) TE-polarized through-port transmission spectra of a critically coupled Si waveguide ring resonator without a VO2 tab. The resonator Q is unchanged for substrate temperatures between 30 °C and 100 °C; however, grating coupling efficiency is impacted by the thermo-optic effect in Si, resulting in lower off-resonance transmission. (b) Through-port transmission spectra for increasing substrate temperature with the same resonator geometry, but with a 2 µm-long VO2 tab. Modes of the same azimuthal order are indicated with diamond-shaped markers, revealing a thermally induced redshift of 0.08 nm/°C. (c) Round-trip resonator loss near 1550 nm due to the VO2 tab. Upon cooling, thermal hysteresis of over 30 °C is observed.
. At 30 °C, the resonance at λ 0 = 1550.706 nm has a linewidth, δλ, of 14.1 pm and a FSR, Δλ, of 0.510 nm. By the relation Q = λ 0λ (valid for δλ << λ 0), this corresponds to a loaded quality factor Q ref = 110,000. For Δλ << λ 0, the group index is approximately n g = λ 0 2/(ΔλL) = 3.75, where L = 400π µm is the round-trip length of the ring resonator. By fitting the Lorentzian lineshape of the through-port transmission, T, to the function [19

19. K. Preston and M. Lipson, “Slot waveguides with polycrystalline silicon for electrical injection,” Opt. Express 17(3), 1527–1534 (2009). [CrossRef] [PubMed]

]
T(λ)=(ar)2+(2πngL)2ra(λλ0)2λ04(1ra)2+(2πngL)2ra(λλ0)2λ04,
(1)
we obtain a = 0.951, r = 0.964, and an intrinsic loss per unit length of α int = −20 log(a)/L = 3.47 dB/cm. This corresponds to an intrinsic quality factor of Q int = 4.343×2πn g/(λ 0 α int) = 190,000. We assume the observed Q ref to be a result of both propagation loss and loss due to the through-port coupler, represented here by the coupler quality factor, Q coup, where
1Qref=1Qint+1Qcoup.
(2)
The value of Q coup is therefore 261,000, which corresponds to a coupler loss of l coup = 4.343×2πn g L/(λ 0 Q coup) = 0.32 dB per pass in the resonator. The same value can be obtained from the Lorentzian fitting parameter r, where l coup = −20 log(r).

We also observe that the off-resonance transmission for the reference devices is decreased when the sample is heated. Changes in the Si refractive index shift the ideal coupling angle of the grating couplers, resulting in decreased coupling efficiency of our devices when the angle is fixed. This illustrates the advantage of using resonator linewidth to probe attenuation: as long as the optical power is low enough that nonlinear effects are negligible, the linewidth provides an intensive measure of loss that is independent of coupled power. Consistent with the assumption of linearity, we measured no change in linewidth with input power for the laser intensities used here.

We then characterized ring resonators with VO2 tabs patterned opposite the though-port coupler. Tabs with a 2-µm device length proved most conducive to the measurement technique employed here, as they were long enough to significantly perturb the ring resonator modes, but not so long as to absorb more light than is needed to reliably measure linewidth. The spectral response, shown in Fig. 3(b), was measured in the same manner as the reference resonator, and the substrate temperature was increased by 5 °C between measurements (for brevity, not all temperatures are shown in the figure). The sample was allowed to thermally stabilize for several minutes between measurements to eliminate transient effects in the VO2. As expected based on the VO2 refractive index, the presence of the tab significantly decreases the loaded quality factor, Q load, of the TE resonator modes. Using the loaded quality factor of the otherwise identical reference resonator, Q ref, we can isolate the effect of the tab by the relation
1Qload=1Qint+1Qcoup+1Qtab=1Qref+1Qtab.
(3)
The single-pass loss induced by the tab is therefore l tab = 4.343×2πn g L/(λ 0 Q tab), where n g is unchanged from the reference resonator, as the tab length is just a small fraction of L.

At 30 °C, we observe Q load = 30,000, and the quality factor decreases rapidly near the VO2 phase transition temperature at 68 °C, ultimately falling to Q load = 8,900 at 100 °C. These values of Q load correspond to a modulator loss of 2.0 dB when the VO2 is in its insulating phase and 8.6 dB for the metallic phase, as shown in Fig. 3(c), which is a 78% decrease in transmission. We define a modulator figure of merit (FOM) as the ratio of the modulation depth to the insulating-phase insertion loss, equal to 3.3 in this case.

We observe that as the sample is cooled from 100 °C, the VO2 tab retains its metallic properties down to nearly 40 °C. As mentioned previously, such broad thermal hysteresis is characteristic of films with the large-grain microstructure observed here, where there is a relatively low density of nucleation sites for the metal-to-insulator transition. The width of the hysteresis loop matches our observations of electrical resistivity versus temperature, except that the onset of the metal-to-insulator transition during cooling is not as apparent in the optical measurements until the phase transition is nearly complete. During cooling, we also observe no anomalous increase in loss near the phase transition, suggesting that the nucleation of insulating domains in the VO2 does not lead to isolation of metallic regions while the film still exhibits strongly metallic optical properties. We note that hysteresis can be undesirable in certain applications and could be reduced by preparing films with smaller crystal grains at lower temperatures [17

17. J. Y. Suh, R. Lopez, L. C. Feldman, and R. F. Haglund Jr., “Semiconductor to metal phase transition in the nucleation and growth of VO2 nanoparticles and thin films,” J. Appl. Phys. 96(2), 1209–1213 (2004). [CrossRef]

], but broad hysteresis could be useful, for example, in optical memory devices.

5. Comparison with modeling

We also performed three-dimensional finite-difference time-domain (FDTD) calculations (Lumerical) with the waveguide structure shown in Fig. 4(b). Our idealized structure resembles the fabricated one except for the roughness of the polycrystalline VO2; however, agreement of calculated loss with experiments further suggests that surface scattering is negligible compared with absorption. To obtain modulator loss with the FDTD simulations, we used the fundamental TE mode of the bare Si waveguide at 1550 nm as an input source and recorded the normalized reflected and transmitted power. The reflected power was found to be less than 0.2% for all tab geometries considered here, so excess loss beyond that due to VO2 absorption is attributed to scattering into unguided modes. Consistent with the assertion that material loss is dominant for both VO2 phases, loss increases linearly with device length, as seen in Fig. 5(a)
Fig. 5 (a) Simulated TE-mode loss due to a 65 nm-thick VO2 tab as a function of tab length calculated using the three-dimensional FDTD method. The predicted losses for a 2-µm tab are within 5% of the measured values. (b) Simulated loss per unit length as a function of VO2 film thickness. The dashed black curve is the modulator figure of merit, defined as the ratio of the modulation depth to the insertion loss.
, and loss is minimal as the device length approaches zero. For a modulator with the experimental geometry, the insulating-phase loss is 2.1 dB and the metallic-phase loss is 8.2 dB, which agrees to within 5% of the measured values.

6. Summary

We have demonstrated a compact VO2-based absorption modulator at λ = 1550 nm on a Si waveguide platform as a potential component for future integrated optical circuits. While large-diameter ring resonators were used to accurately probe modulator loss, we show that in-line modulator devices need only be a few microns long, due to a measured 16-fold increase in material absorption at the VO2 insulator-to-metal phase transition. By directly heating an integrated 2-µm device, we measured a single-pass loss of 2 dB at 30 °C, where VO2 is in its insulating phase, and 8.6 dB at 100 °C, where VO2 has transformed to its metallic phase, corresponding to a 78% decrease in transmission. We note that, as confirmed by electromagnetic simulations, simply extending the device length to 5 µm would result in modulation in excess of 16 dB, which is competitive with MZI and electro-absorption modulators, but the insertion loss in the insulating phase would be increased to 5 dB. Such a device was not quantitatively characterized with the ring-resonator test bed used here, as the large metallic-phase VO2 loss almost completely extinguishes the cavity resonances; however, we envision that future devices will utilize more localized means to induce the phase transition, eliminating the need for a resonator as an accurate temperature-independent probe of modulation. In particular, since the VO2 phase transition can also be induced athermally, future devices can potentially use local optical or electrical stimulus to not only induce the dramatic shift in absorption observed here, but do so on extremely short time scales.

Acknowledgements

References and links

1.

F. J. Morin, “Oxides which show a metal-to-insulator transition at the Neel temperature,” Phys. Rev. Lett. 3(1), 34–36 (1959). [CrossRef]

2.

J. B. Goodenough, “The two components of crystallographic transition in VO2,” J. Solid State Chem. 3(4), 490–500 (1971). [CrossRef]

3.

A. Cavalleri, C. Tóth, C. W. Siders, J. A. Squier, F. Ráksi, P. Forget, and J. C. Kieffer, “Femtosecond structural dynamics in VO2 during an ultrafast solid-solid phase transition,” Phys. Rev. Lett. 87(23), 237401 (2001). [CrossRef] [PubMed]

4.

H. T. Kim, Y. W. Lee, B. J. Kim, B. G. Chae, S. J. Yun, K. Y. Kang, K. J. Han, K. J. Yee, and Y. S. Lim, “Monoclinic and correlated metal phase in VO(2) as evidence of the Mott transition: coherent phonon analysis,” Phys. Rev. Lett. 97(26), 266401 (2006). [CrossRef]

5.

B. G. Chae, H. T. Kim, D. H. Youn, and K. Y. Kang, “Abrupt metal–insulator transition observed in VO2 thin films induced by a switching voltage pulse,” Physica B 369(1-4), 76–80 (2005). [CrossRef]

6.

C. Ko and S. Ramanathan, “Observation of electric field-assisted phase transition in thin film vanadium oxide in a metal-oxide-semiconductor device geometry,” Appl. Phys. Lett. 93(25), 252101 (2008). [CrossRef]

7.

S. Chen, X. Yi, H. Ma, H. Wang, X. Tao, M. Chen, and C. Ke, “A novel structural VO2 micro-optical switch,” Opt. Quantum Electron. 35(15), 1351–1355 (2003). [CrossRef]

8.

L. Jiang and W. N. Carr, “Design, fabrication and testing of a micromachined thermo-optical light modulator based on a vanadium dioxide array,” J. Micromech. Microeng. 14(7), 833–840 (2004). [CrossRef]

9.

Q. Xu, B. Schmidt, S. Pradhan, and M. Lipson, “Micrometre-scale silicon electro-optic modulator,” Nature 435(7040), 325–327 (2005). [CrossRef] [PubMed]

10.

A. Liu, R. Jones, L. Liao, D. Samara-Rubio, D. Rubin, O. Cohen, R. Nicolaescu, and M. Paniccia, “A high-speed silicon optical modulator based on a metal-oxide-semiconductor capacitor,” Nature 427(6975), 615–618 (2004). [CrossRef] [PubMed]

11.

E. L. Wooten, K. M. Kissa, A. Yi-Yan, E. J. Murphy, D. A. Lafaw, P. F. Hallemeier, D. Maack, D. V. Attanasio, D. J. Fritz, G. J. McBrien, and D. E. Bossi, “A review of lithium niobate modulators for fiber-optic communications system,” IEEE J. Sel. Top. Quantum Electron. 6(1), 69–82 (2000). [CrossRef]

12.

T. Ido, S. Tanaka, M. Suzuki, M. Koizumi, H. Sano, and H. Inoue, “Ultra-high-speed multiple-quantum-well electro-absorption optical modulators with integrated waveguides,” J. Lightwave Technol. 14(9), 2026–2034 (1996). [CrossRef]

13.

G. Gopalakrishnan, D. Ruzmetov, and S. Ramanathan, “On the triggering mechanism for the metal-insulator transition in thin film VO2 devices: electric field versus thermal effects,” J. Mater. Sci. 44(19), 5345–5353 (2009). [CrossRef]

14.

G. Stefanovich, A. Pergament, and D. Stefanovich, “Electrical switching and Mott transition in VO2,” J. Phys. Condens. Matter 12(41), 8837–8845 (2000). [CrossRef]

15.

M. A. Webster, R. M. Pafchek, A. Mitchell, and T. L. Koch, “Width dependence of inherent TM-mode lateral leakage loss in silicon-on-insulator ridge waveguides,” IEEE Photon. Technol. Lett. 19(6), 429–431 (2007). [CrossRef]

16.

R. M. Briggs, M. Shearn, A. Scherer, and H. A. Atwater, “Wafer-bonded single-crystal silicon slot waveguides and ring resonators,” Appl. Phys. Lett. 94(2), 021106 (2009). [CrossRef]

17.

J. Y. Suh, R. Lopez, L. C. Feldman, and R. F. Haglund Jr., “Semiconductor to metal phase transition in the nucleation and growth of VO2 nanoparticles and thin films,” J. Appl. Phys. 96(2), 1209–1213 (2004). [CrossRef]

18.

L. J. van der Pauw, “A new method of measuring the resistivity and Hall coefficients on lamellae of arbitrary shape,” Philips Tech. Rev. 20, 220–224 (1958).

19.

K. Preston and M. Lipson, “Slot waveguides with polycrystalline silicon for electrical injection,” Opt. Express 17(3), 1527–1534 (2009). [CrossRef] [PubMed]

20.

R. A. Soref and B. R. Bennett, “Electrooptical effects in silicon,” IEEE J. Quantum Electron. 23(1), 123–129 (1987). [CrossRef]

21.

M. Borselli, T. J. Johnson, and O. Painter, “Beyond the Rayleigh scattering limit in high-Q silicon microdisks: theory and experiment,” Opt. Express 13(5), 1515–1522 (2005). [CrossRef] [PubMed]

22.

J. A. McCaulley, V. M. Donnelly, M. Vernon, and I. Taha, “Temperature dependence of the near-infrared refractive index of silicon gallium arsenide, and indium phosphide,” Phys. Rev. B 49(11), 7408–7417 (1994). [CrossRef]

23.

H. S. Choi, J. S. Ahn, J. H. Jung, T. W. Noh, and D. H. Kim, “Mid-infrared properties of a VO2 film near the metal-insulator transition,” Phys. Rev. B 54(7), 4621–4628 (1996). [CrossRef]

OCIS Codes
(130.3120) Integrated optics : Integrated optics devices
(160.6840) Materials : Thermo-optical materials
(230.5750) Optical devices : Resonators
(230.7380) Optical devices : Waveguides, channeled
(130.4110) Integrated optics : Modulators

ToC Category:
Integrated Optics

History
Original Manuscript: March 23, 2010
Revised Manuscript: April 29, 2010
Manuscript Accepted: May 4, 2010
Published: May 12, 2010

Citation
Ryan M. Briggs, Imogen M. Pryce, and Harry A. Atwater, "Compact silicon photonic waveguide modulator based on the vanadium dioxide metal-insulator phase transition," Opt. Express 18, 11192-11201 (2010)
http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-18-11-11192


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References

  1. F. J. Morin, “Oxides which show a metal-to-insulator transition at the Neel temperature,” Phys. Rev. Lett. 3(1), 34–36 (1959). [CrossRef]
  2. J. B. Goodenough, “The two components of crystallographic transition in VO2,” J. Solid State Chem. 3(4), 490–500 (1971). [CrossRef]
  3. A. Cavalleri, C. Tóth, C. W. Siders, J. A. Squier, F. Ráksi, P. Forget, and J. C. Kieffer, “Femtosecond structural dynamics in VO2 during an ultrafast solid-solid phase transition,” Phys. Rev. Lett. 87(23), 237401 (2001). [CrossRef] [PubMed]
  4. H. T. Kim, Y. W. Lee, B. J. Kim, B. G. Chae, S. J. Yun, K. Y. Kang, K. J. Han, K. J. Yee, and Y. S. Lim, “Monoclinic and correlated metal phase in VO(2) as evidence of the Mott transition: coherent phonon analysis,” Phys. Rev. Lett. 97(26), 266401 (2006). [CrossRef]
  5. B. G. Chae, H. T. Kim, D. H. Youn, and K. Y. Kang, “Abrupt metal–insulator transition observed in VO2 thin films induced by a switching voltage pulse,” Physica B 369(1-4), 76–80 (2005). [CrossRef]
  6. C. Ko and S. Ramanathan, “Observation of electric field-assisted phase transition in thin film vanadium oxide in a metal-oxide-semiconductor device geometry,” Appl. Phys. Lett. 93(25), 252101 (2008). [CrossRef]
  7. S. Chen, X. Yi, H. Ma, H. Wang, X. Tao, M. Chen, and C. Ke, “A novel structural VO2 micro-optical switch,” Opt. Quantum Electron. 35(15), 1351–1355 (2003). [CrossRef]
  8. L. Jiang and W. N. Carr, “Design, fabrication and testing of a micromachined thermo-optical light modulator based on a vanadium dioxide array,” J. Micromech. Microeng. 14(7), 833–840 (2004). [CrossRef]
  9. Q. Xu, B. Schmidt, S. Pradhan, and M. Lipson, “Micrometre-scale silicon electro-optic modulator,” Nature 435(7040), 325–327 (2005). [CrossRef] [PubMed]
  10. A. Liu, R. Jones, L. Liao, D. Samara-Rubio, D. Rubin, O. Cohen, R. Nicolaescu, and M. Paniccia, “A high-speed silicon optical modulator based on a metal-oxide-semiconductor capacitor,” Nature 427(6975), 615–618 (2004). [CrossRef] [PubMed]
  11. E. L. Wooten, K. M. Kissa, A. Yi-Yan, E. J. Murphy, D. A. Lafaw, P. F. Hallemeier, D. Maack, D. V. Attanasio, D. J. Fritz, G. J. McBrien, and D. E. Bossi, “A review of lithium niobate modulators for fiber-optic communications system,” IEEE J. Sel. Top. Quantum Electron. 6(1), 69–82 (2000). [CrossRef]
  12. T. Ido, S. Tanaka, M. Suzuki, M. Koizumi, H. Sano, and H. Inoue, “Ultra-high-speed multiple-quantum-well electro-absorption optical modulators with integrated waveguides,” J. Lightwave Technol. 14(9), 2026–2034 (1996). [CrossRef]
  13. G. Gopalakrishnan, D. Ruzmetov, and S. Ramanathan, “On the triggering mechanism for the metal-insulator transition in thin film VO2 devices: electric field versus thermal effects,” J. Mater. Sci. 44(19), 5345–5353 (2009). [CrossRef]
  14. G. Stefanovich, A. Pergament, and D. Stefanovich, “Electrical switching and Mott transition in VO2,” J. Phys. Condens. Matter 12(41), 8837–8845 (2000). [CrossRef]
  15. M. A. Webster, R. M. Pafchek, A. Mitchell, and T. L. Koch, “Width dependence of inherent TM-mode lateral leakage loss in silicon-on-insulator ridge waveguides,” IEEE Photon. Technol. Lett. 19(6), 429–431 (2007). [CrossRef]
  16. R. M. Briggs, M. Shearn, A. Scherer, and H. A. Atwater, “Wafer-bonded single-crystal silicon slot waveguides and ring resonators,” Appl. Phys. Lett. 94(2), 021106 (2009). [CrossRef]
  17. J. Y. Suh, R. Lopez, L. C. Feldman, and R. F. Haglund., “Semiconductor to metal phase transition in the nucleation and growth of VO2 nanoparticles and thin films,” J. Appl. Phys. 96(2), 1209–1213 (2004). [CrossRef]
  18. L. J. van der Pauw, “A new method of measuring the resistivity and Hall coefficients on lamellae of arbitrary shape,” Philips Tech. Rev. 20, 220–224 (1958).
  19. K. Preston and M. Lipson, “Slot waveguides with polycrystalline silicon for electrical injection,” Opt. Express 17(3), 1527–1534 (2009). [CrossRef] [PubMed]
  20. R. A. Soref and B. R. Bennett, “Electrooptical effects in silicon,” IEEE J. Quantum Electron. 23(1), 123–129 (1987). [CrossRef]
  21. M. Borselli, T. J. Johnson, and O. Painter, “Beyond the Rayleigh scattering limit in high-Q silicon microdisks: theory and experiment,” Opt. Express 13(5), 1515–1522 (2005). [CrossRef] [PubMed]
  22. J. A. McCaulley, V. M. Donnelly, M. Vernon, and I. Taha, “Temperature dependence of the near-infrared refractive index of silicon gallium arsenide, and indium phosphide,” Phys. Rev. B 49(11), 7408–7417 (1994). [CrossRef]
  23. H. S. Choi, J. S. Ahn, J. H. Jung, T. W. Noh, and D. H. Kim, “Mid-infrared properties of a VO2 film near the metal-insulator transition,” Phys. Rev. B 54(7), 4621–4628 (1996). [CrossRef]

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