All-optical switching on a silicon chip

Almeida, Vilson R.; Barrios, Carlos Angulo; Panepucci, Roberto R.; Lipson, Michal; Foster, Mark A.; Ouzounov, Dimitre G.; Gaeta, Alexander L.

doi:10.1364/ol.29.002867

Cited by 213 publications

(143 citation statements)

References 18 publications

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“…[8] Last but not least, ultrafast control of photonic crystals is important for controlling the propagation of light, such as in switched macroporous silicon, [9] or 2D crystal slabs. [10] In optical switching experiments, four important requirements have to be met. [6] First of all, the magnitude of the induced change in the real part of the refractive index n ′ must be large enough to obtain the desired effect.…”

Section: Introductionmentioning

confidence: 99%

Spatial homogeneity of optically switched semiconductor photonic crystals and of bulk semiconductors

Vos¹

2005

Journal of Applied Physics

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This paper discusses free carrier generation by pulsed laser fields as a mechanism to switch the optical properties of semiconductor photonic crystals and bulk semiconductors on an ultrafast time scale. Requirements are set for the switching magnitude, the time-scale, the induced absorption as well as the spatial homogeneity, in particular for silicon at λ = 1550 nm. Using a nonlinear absorption model, we calculate carrier depth profiles and define a homogeneity length ℓ hom . Homogeneity length contours are visualized in a plane spanned by the linear and two-photon absorption coefficients. Such a generalized homogeneity plot allows us to find optimum switching conditions at pump frequencies near ν/c=5000 cm −1 (λ = 2000 nm). We discuss the effect of scattering in photonic crystals on the homogeneity. We experimentally demonstrate a 10% refractive index switch in bulk silicon within 230 fs with a lateral homogeneity of more than 30 µm. Our results are relevant for switching of modulators in absence of photonic crystals.

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Section: Introductionmentioning

confidence: 99%

Spatial homogeneity of optically switched semiconductor photonic crystals and of bulk semiconductors

Vos¹

2005

Journal of Applied Physics

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“…At present techniques for local refractive index modulation in photonic structures is limited to the exploitation of relatively weak non-linear material properties [4,5], where ∆n/n (where n is the index of refraction) on the order of 10 -3 or lower, and thus requiring either long interaction lengths, high operational power, or the incorporation of resonant elements to enhance the effect. Techniques such as mechanical deformation [6], thermooptics [7], liquid crystal infusion [8], liquid-fluid infusion [9,11] and others [12,15] offer much higher effective ∆n/n.…”

Section: Introductionmentioning

confidence: 99%

Integration of Sub-Wavelength Nanofluidics With Photonic Crystals

et al. 2005

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ABSTRACT"Optofluidics" represents the marriage of optics, optoelectronics and nanophotonics with fluidics. Such integration represents a new approach for dynamic manipulation of optical properties at length scales both greater than and smaller than the wavelength of light with applications ranging from reconfigurable photonic circuits to fluidically adaptable optics to high sensitivity bio-detection currently under development. The capabilities in terms of fluidic control, mixing, miniaturization and optical property tuning afforded by micro-, nano-fluidics combined with soft lithography based fabrication provides an ideal platform upon which to build such devices. Here we present our technique for integrating soft lithography based nanofluidics with e-beam lithography defined silicon-on-insulator photonic crystals. We demonstrate nanofluidic addressability of single, sub-wavelength, defects within the planar photonic crystal and the dynamic tuning of the guided mode. In this paper we focus on the fabrication, integration and experimental details of this work. INTRODUCTIONPhotonic crystals [1] are attractive for controlling optical propagation by introducing pre-engineered defects into an otherwise regular lattice to create spectral filters, tight bend waveguides, resonant cavities [2] and highly efficient lasers [3]. At present techniques for local refractive index modulation in photonic structures is limited to the exploitation of relatively weak non-linear material properties [4,5], where ∆n/n (where n is the index of refraction) on the order of 10 -3 or lower, and thus requiring either long interaction lengths, high operational power, or the incorporation of resonant elements to enhance the effect. Techniques such as mechanical deformation [6], thermooptics [7], liquid crystal infusion [8], liquid-fluid infusion [9,11] and others [12,15] offer much higher effective ∆n/n. At present, however, these methods rely on globally modifying the refractive index of the entire device. Thus whereas local tunability over small interaction lengths requires the high ∆n/n afforded by these global approaches, the ability to perform such manipulations with the sub-micron scale precision required for advanced photonic devices remains elusive. The development of such a technique could enable the creation of a new class of ultra-compact adaptable photonic circuits.Nanofluidics provides a solution that enables both localized control and high refractive index modulation. By using modern nanofabrication techniques fluidic networks can be built which confine flows on scales much smaller than the wavelength of the transmitted light and enable the direct infusement and exchange of liquids with interesting optical properties (e.g. varying refractive index, gain and non-linearity) directly into the nanophotonic structure. As a first step in the development of two dimensional reconfigurable photonic circuits, here we demonstrate the nanofluidic addressing of a single defect row of holes within a two dimensional photonic crystal. We begin...

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“…Previous tuning operations were mostly achieved by changing the refractive index of the materials of microring resonators. The already presented tuning mechanisms included the use of free-carrier dispersion effect 9 and thermo-optic effect 13 . The free carriers and the thermal nonlinear optical effect required for tuning can be generated either electrically or optically, enabling different applications including electro-optic modulators, optical switches, optical routers, optical logic functions, and optical memories 14 .…”

mentioning

confidence: 99%

Optically-controlled extinction ratio and Q-factor tunable silicon microring resonators based on optical forces

Long

Wang

et al. 2013

2013 IEEE Photonics Conference

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Tunability is a desirable property of microring resonators to facilitate superior performance. Using light to control light, we present an alternative simple approach to tuning the extinction ratio (ER) and Q-factor of silicon microring resonators based on optical forces. We design an opto-mechanical tunable silicon microring resonator consisting of an add-drop microring resonator and a control-light-carrying waveguide (''controlling'' waveguide). One of the two bus waveguides of the microring resonator is a deformable nanostring put in parallel with the ''controlling'' waveguide. The tuning mechanism relies on the optical force induced deflection of suspended nanostring, leading to the change of coupling coefficient of microring and resultant tuning of ER and Q-factor. Two possible geometries, i.e. double-clamped nanostring and cantilever nanostring, are studied in detail for comparison. The obtained results imply a favorable structure with the microring positioned at the end of the cantilever nanostring. It features a wide tuning range of ER from 5.6 to 39.9 dB and Q-factor from 309 to 639 as changing the control power from 0 to 1.4 mW. Silicon photonics has become one of the most promising photonic integration platforms in the recent years owing to its small footprint, reduced power consumption, and availability of complementary metal-oxidesemiconductor (CMOS) fabrication technology [1][2][3][4][5][6] . The attractive small footprint feature of silicon waveguide structures is because of the high refractive index contrast between silicon and its oxide or air, which enables tight light confinement and benefits small bending radius of waveguide. Because of its unprecedented small size for potential high-density photonic interaction, silicon microring resonator, i.e. compact bended silicon waveguide in a small loop configuration, is of great importance to accelerate the success of silicon photonics 7 . Silicon microring resonators have been employed to facilitate miscellaneous applications, such as sensors 8 , modulators Generally speaking, all the optical properties of a passive silicon microring resonator, e.g. resonance wavelength, free spectral range, extinction ratio (ER), quality factor (Q-factor), are predetermined by the structure design and thus fixed once fabricated. In particular, it is always common to see the offset between the actually achieved properties and preliminarily designed ones due to the unavoidable fabrication errors. Hence, tunability of microring resonators is highly desirable in practical applications to facilitate superior performance. Previous tuning operations were mostly achieved by changing the refractive index of the materials of microring resonators. The already presented tuning mechanisms included the use of free-carrier dispersion effect 9 and thermo-optic effect 13 . The free carriers and the thermal nonlinear optical effect required for tuning can be generated either electrically or optically, enabling different applications including electro-optic modulators, optical switch...

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All-optical switching on a silicon chip

Cited by 213 publications

References 18 publications

Spatial homogeneity of optically switched semiconductor photonic crystals and of bulk semiconductors

Spatial homogeneity of optically switched semiconductor photonic crystals and of bulk semiconductors

Integration of Sub-Wavelength Nanofluidics With Photonic Crystals

Optically-controlled extinction ratio and Q-factor tunable silicon microring resonators based on optical forces

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