High-contrast 40 Gb/s operation of a 500 um long silicon carrier-depletion slow wave modulator

This paper was published in OPTICS LETTERS and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://dx.doi.org/10.1364/OL.37.003504. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law[EN] In this Letter, we demonstrate a highly efficient, compact, high-contrast and low-loss silicon slow wave modulator based on a traveling-wave Mach¿Zehnder interferometer with two 500 μm long slow wave phase shifters. 40 Gb ∕ s operation with 6.6 dB extinction ratio at quadrature and with an on-chip insertion loss of only 6 dB is shown. These results confirm the benefits of slow light as a means to enhance the performance of silicon modulators based on the plasma dispersion effect.Funding by the European Commission (EC) under project Photonics Electronics Functional Integration on CMOS (HELIOS) (FP7224312) and PROMETEO-2010- 087 R&D Excellency Program are acknowledged. F.Y.G, D.J.T. and G.T.R. acknowledge funding support from the United Kingdom Engineering and Physical Sciences Research Council (EPSRC) under the grant “UK Silicon Photonics”.Brimont, ACJ.; Thomson, DJ.; Gardes, FY.; Fedeli, JM.; Reed, GT.; Martí Sendra, J.; Sanchis Kilders, P. (2012). High-contrast 40 Gb/s operation of a 500 um long silicon carrier-depletion slow wave modulator. Optics Letters. 37(17):3504-3506. https://doi.org/10.1364/OL.37.003504S350435063717Liao, L., Liu, A., Rubin, D., Basak, J., Chetrit, Y., Nguyen, H., … Paniccia, M. (2007). 40 Gbit/s silicon optical modulator for high-speed applications. Electronics Letters, 43(22), 1196. doi:10.1049/el:20072253Gardes, F. Y., Thomson, D. J., Emerson, N. G., & Reed, G. T. (2011). 40 Gb/s silicon photonics modulator for TE and TM polarisations. Optics Express, 19(12), 11804. doi:10.1364/oe.19.011804Thomson, D. J., Gardes, F. Y., Hu, Y., Mashanovich, G., Fournier, M., Grosse, P., … Reed, G. T. (2011). High contrast 40Gbit/s optical modulation in silicon. Optics Express, 19(12), 11507. doi:10.1364/oe.19.011507Brimont, A., Thomson, D. J., Sanchis, P., Herrera, J., Gardes, F. Y., Fedeli, J. M., … Martí, J. (2011). High speed silicon electro-optical modulators enhanced via slow light propagation. Optics Express, 19(21), 20876. doi:10.1364/oe.19.020876Ziebell, M., Marris-Morini, D., Rasigade, G., Fédéli, J.-M., Crozat, P., Cassan, E., … Vivien, L. (2012). 40 Gbit/s low-loss silicon optical modulator based on a pipin diode. Optics Express, 20(10), 10591. doi:10.1364/oe.20.010591Dong, P., Chen, L., & Chen, Y. (2012). High-speed low-voltage single-drive push-pull silicon Mach-Zehnder modulators. Optics Express, 20(6), 6163. doi:10.1364/oe.20.006163Taylor, H. F. (1999). Enhanced electrooptic modulation efficiency utilizing slow-wave optical propagation. Journal of Lightwave Technology, 17(10), 1875-1883. doi:10.1109/50.793770O’Faolain, L., Beggs, D. M., White, T. P., Kampfrath, T., Kuipers, K., & Krauss, T. F. (2010). Compact Optical Switches and Modulators Based on Dispersion Engineered Photonic Crystals. IEEE Photonics Journal, 2(3), 404-414. doi:10.1109/jphot.2010.2047918Brimont, A., Vicente Galán, J., Maria Escalante, J., Martí, J., & Sanchis, P. (2010). Group-index engineering in silicon corrugated waveguides. Optics Letters, 35(16), 2708. doi:10.1364/ol.35.002708Soref, R., & Bennett, B. (1987). Electrooptical effects in silicon. IEEE Journal of Quantum Electronics, 23(1), 123-129. doi:10.1109/jqe.1987.1073206Nguyen, H. C., Sakai, Y., Shinkawa, M., Ishikura, N., & Baba, T. (2011). 10 Gb/s operation of photonic crystal silicon optical modulators. Optics Express, 19(14), 13000. doi:10.1364/oe.19.013000Dong, P., Liao, S., Liang, H., Qian, W., Wang, X., Shafiiha, R., … Asghari, M. (2010). High-speed and compact silicon modulator based on a racetrack resonator with a 1 V drive voltage. Optics Letters, 35(19), 3246. doi:10.1364/ol.35.00324

Silicon slow-light-based photonic mixer for microwave-frequencyconversion applications

This paper was published in OPTICS LETTERS and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://dx.doi.org/10.1364/OL.37.001721. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law[EN] We describe and demonstrate experimentally a method for photonic mixing of microwave signals by using a silicon electro-optical Mach¿Zehnder modulator enhanced via slow-light propagation. Slow light with a group index of ~11, achieved in a one-dimensional periodic structure, is exploited to improve the upconversion performance of an input frequency signal from 1 to 10.25 GHz. A minimum transmission point is used to successfully demonstrate the upconversion with very low conversion losses of ~7¿¿dB and excellent quality of the received I/Q modulated QPSK signal with an optimum EVM of ~8%.Financial support from FP7-224312 HELIOS project and Generalitat Valenciana under PROMETEO-2010-087 R&D Excellency Program (NANOMET) are acknowledged. F. Y.Gardes, D. J. Thomson, and G. T. Reed are supported by funding received from the UK EPSRC funding body under the grant “UK Silicon Photonics.” The author A. M. Gutiérrez thanks D. Marpaung for his useful help.Gutiérrez Campo, AM.; Brimont, ACJ.; Herrera Llorente, J.; Aamer, M.; Martí Sendra, J.; Thomson, DJ.; Gardes, FY.... (2012). Silicon slow-light-based photonic mixer for microwave-frequencyconversion applications. Optics Letters. 37(10):1721-1723. https://doi.org/10.1364/OL.37.001721S17211723371

Tuning silicon-rich nitride microring resonances with graphene capacitors for high-performance computing applications

This is the final version. Available from the Optical Society of America via the DOI in this record.We demonstrate the potential of a graphene capacitor structure on silicon-richnitride micro-ring resonators for multitasking operations within high performance computing.Capacitor structures formed by two graphene sheets separated by a 10 nm insulating siliconnitride layer are considered. Hybrid integrated photonic structures are then designed to exploitthe electro-absorptive operation of the graphene capacitor to tuneably control the transmissionand attenuation of different wavelengths of light. By tuning the capacitor length, a shift in theresonant wavelength is produced giving rise to a broadband multilevel photonic volatile memory.The advantages of using silicon-rich nitride as the waveguiding material in place of the moreconventional silicon nitride (Si3N4) are shown, with a doubling of the device’s operationalbandwidth from 31.2 to 62.41 GHz achieved while also allowing a smaller device footprint.A systematic evaluation of the device’s performance and energy consumption is presented.A difference in the extinction ratio between the ON and OFF states of 16.5 dB and energyconsumptions of<0.3 pJ/bit are obtained. Finally, it has been demonstrated that increasing thepermittivity of the insulator layer in the capacitor structure, the energy consumption per bit canbe reduced even further. Overall, the resonance tuning enabled by the novel graphene capacitormakes it a key component for future multilevel photonic memories and optical routing in highperformance computing.Engineering and Physical Sciences Research Council (EPSRC

Functional kernel estimators of conditional extreme quantiles

We address the estimation of "extreme" conditional quantiles i.e. when their order converges to one as the sample size increases. Conditions on the rate of convergence of their order to one are provided to obtain asymptotically Gaussian distributed kernel estimators. A Weissman-type estimator and kernel estimators of the conditional tail-index are derived, permitting to estimate extreme conditional quantiles of arbitrary order.Comment: arXiv admin note: text overlap with arXiv:1107.226

Recent breakthroughs in carrier depletion based silicon optical modulators

The majority of the most successful optical modulators in silicon demonstrated in recent years operate via the plasma dispersion effect and are more specifically based upon free carrier depletion in a silicon rib waveguide. In this work we overview the different types of free carrier depletion type optical modulators in silicon. A summary of some recent example devices for each configuration is then presented together with the performance that they have achieved. Finally an insight into some current research trends involving silicon based optical modulators is provided including integration, operation in the mid-infrared wavelength range and application in short and long haul data transmission link

O-band N-rich silicon nitride MZI based on GST

This is the author accepted manuscript. The final version is available from the publisher via the DOI in this recordWe have experimentally demonstrated an O-band Mach-Zehnder interferometer (MZI) based on a N-rich silicon nitride platform combined with Ge2Sb2Te5 for future optical communication applications. The device operation relies on controlling the waveguide’s losses using a phase change material cell which can be changed from amorphous (lowloss) to crystalline (high-loss). An extinction ratio (ER) as high as 11 dB was obtained between the amorphous (ON) and the crystalline (OFF) states of the MZI optical building block. The insertion loss of the MZI structure per cell unit length was measured to be as high as 0.87 dB/µm in OFF state and as low as 0.064 dB/µm in ON state for TM polarisation.Engineering and Physical Sciences Research Council (EPSRC

Reconfigurable photonic integrated circuits (RPICs) based on functional materials for integrated optical communication applications

This is the final version. Available from the publisher via the DOI in this record.In this work we combine the already mature silicon and silicon nitride platforms with novel reconfigurable materials such as 2D materials, liquid crystals and phase change materials. An actively reconfigurable 1D photonic crystal multi-channel filter based on Si-on-insulator and liquid crystal platforms is demonstrated with extraordinary large quality factor, Q ∼ 104 . A complete study and design of an optical routing and multilevel volatile photonic memory based on graphene capacitor concept for future high performance computing using Silicon rich nitride is shown with a bandwidth of 64 GHz and energy power consumption per bit as low as 0.22 pJ. Finally, an optical switch based on germanium-antimony-tellurium phase change material (GST) is experimentally demonstrated for O-band operation with the extinction ratio as high as 10 dB between the amorphous and the crystalline statesEngineering and Physical Sciences Research Council (EPSRC

Three-Terminal Junctions operating as mixers, frequency doublers and detectors: A broad-band frequency numerical and experimental study at room temperature

The frequency response of nanometric T- and Y-shaped three-terminal junctions (TTJs) is investigated experimentally and numerically. In virtue of the parabolic down-bending of the output voltage of the central branch obtained at room temperature under a push-pull fashion input, we analyze: the low-frequency performance (<1 MHz) of TTJs operating as mixers, their RF capability as doublers up to 4 GHz and detection at 94 GHz. Special attention is paid to the impedance matching and cut-off frequency of the measurement set-up. The numerical study is done by means of Monte Carlo simulations. We illustrate the intrinsic functionality of the device as frequency doubler or rectifier up to THz. The role of the width of the central branch on the highfrequency response is also explored, finding different cut-off frequencies for doubling and detection as a consequence of the diverse working principles of both mechanisms and the particular geometry of the TTJs.ROOTHz (FP7-243845

10 Gbit/s error-free DPSK modulation using a push-pull dual-drive silicon modulator

[EN] We experimentally demonstrate a high-speed differential phase shift keying (DPSK) modulation using a silicon push-pull operated dual-drive Mach Zehnder modulator (MZM) based on carrier depletion. 5 Gbit/s and 10 Gbit/s error-free modulation is demonstrated by demodulating the generated DPSK modulated signal using a demodulation circuit based on a polarization delay interferometer through the use of a differential group delay (DGD). Furthermore, the potential for higher DPSK modulation speeds up to 20 Gbit/s is also demonstrated. The obtained results validate the potential to achieve higher order modulation formats, such as quadrature phase shift keying (QPSK), by arranging the MZM in a nested configuration. (C) 2013 Elsevier B.V. All rights reserved.Financial supports from HELIOS (Photonics Electronics Functional Integration on CMOS) FP7-224312 and Generalitat Valenciana under PROMETEO-2010-087 R&D Excellency Program (NANOMET) are acknowledged. M. Aamer and P. Sanchis thank Dr. Javier Herrera for his useful help. D.J. Thomson, F.Y. Gardes and G.T. Reed are supported by funding received from the UK EPSRC funding body under the grant “UK Silicon Photonics”.Aamer, M.; Thomson, DJ.; Gutiérrez Campo, AM.; Brimont, ACJ.; Gardes, FY.; Reed, GT.; Fedeli, JM.... (2013). 10 Gbit/s error-free DPSK modulation using a push-pull dual-drive silicon modulator. Optics Communications. 304:107-110. https://doi.org/10.1016/j.optcom.2013.04.051S10711030