Charged di-boson production at the LHC in a 4-site model with a composite Higgs boson

We investigate the scope of the LHC in probing the parameter space of a 4-site model supplemented by one composite Higgs state, assuming all past, current and future energy and luminosity stages of the CERN machine. We concentrate on the yield of charged di-boson production giving two opposite-charge different-flavour leptons and missing (transverse) energy, i.e., events induced via the subprocess $q\bar q\to e^+\nu_e \mu^-\bar\nu_\mu$ + ${\rm{c.c.}}$, which enables the production in the intermediate step of all additional neutral and charged gauge bosons belonging to the spectrum of this model, some of which in resonant topologies. We find this channel accessible over the background at all LHC configurations after a dedicated cut-based analysis. We finally compare the yield of the di-boson mode to that of Drell-Yan processes and establish that they have complementary strengths, one covering regions of parameter space precluded to the others and vice versa.Comment: 36 pages, 13 figures, 13 table

Demonstration of a heterogeneously integrated III-V/SOI single wavelength tunable laser

A heterogeneously integrated III-V-on-silicon laser is reported, integrating a III-V gain section, a silicon ring resonator for wavelength selection and two silicon Bragg grating reflectors as back and front mirrors. Single wavelength operation with a side mode suppression ratio higher than 45 dB is obtained. An output power up to 10 mW at 20 °C and a thermo-optic wavelength tuning range of 8 nm are achieved. The laser linewidth is found to be 1.7 MHz

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

Silicon photonic Mach Zehnder modulators for next-generation short-reach optical communication networks

Communication traffic grows relentlessly in today’s networks, and with ever more machines connected to the network, this trend is set to continue for the foreseeable future. It is widely accepted that increasingly faster communications are required at the point of the end users, and consequently optical transmission plays a progressively greater role even in short- and medium-reach networks. Silicon photonic technologies are becoming increasingly attractive for such networks, due to their potential for low cost, energetically efficient, high-speed optical components. A representative example is the silicon-based optical modulator, which has been actively studied. Researchers have demonstrated silicon modulators in different types of structures, such as ring resonators or slow light based devices. These approaches have shown remarkably good performance in terms of modulation efficiency, however their operation could be severely affected by temperature drifts or fabrication errors. Mach-Zehnder modulators (MZM), on the other hand, show good performance and resilience to different environmental conditions. In this paper we present a CMOS-compatible compact silicon MZM. We study the application of the modulator to short-reach interconnects by realizing data modulation using some relevant advanced modulation formats, such as 4-level Pulse Amplitude Modulation (PAM-4) and Discrete Multi-Tone (DMT) modulation and compare the performance of the different systems in transmission

Silicon-organic hybrid electro-optical devices

Organic materials combined with strongly guiding silicon waveguides open the route to highly efficient electro-optical devices. Modulators based on the so-called silicon-organic hybrid (SOH) platform have only recently shown frequency responses up to 100 GHz, high-speed operation beyond 112 Gbit/s with fJ/bit power consumption. In this paper, we review the SOH platform and discuss important devices such as Mach-Zehnder and IQ-modulators based on the linear electro-optic effect. We further show liquid-crystal phase-shifters with a voltage-length product as low as V pi L = 0.06 V.mm and sub-mu W power consumption as required for slow optical switching or tuning optical filters and devices

40 Gbit/s silicon-organic hybrid (SOH) phase modulator

A 40 Gbit/s electro-optic modulator is demonstrated. The modulator is based on a slotted silicon waveguide filled with an organic material. The silicon organic hybrid (SOH) approach allows combining highly nonlinear electro-optic organic materials with CMOS-compatible silicon photonics technology

Constraining primordial non-Gaussianity with cosmological weak lensing: shear and flexion

We examine the cosmological constraining power of future large-scale weak lensing surveys on the model of \emph{Euclid}, with particular reference to primordial non-Gaussianity. Our analysis considers several different estimators of the projected matter power spectrum, based on both shear and flexion, for which we review the covariances and Fisher matrices. The bounds provided by cosmic shear alone for the local bispectrum shape, marginalized over $\sigma_8$, are at the level of $\Delta f_\mathrm{NL} \sim 100$. We consider three additional bispectrum shapes, for which the cosmic shear constraints range from $\Delta f_\mathrm{NL}\sim 340$ (equilateral shape) up to $\Delta f_\mathrm{NL}\sim 500$ (orthogonal shape). The competitiveness of cosmic flexion constraints against cosmic shear ones depends on the galaxy intrinsic flexion noise, that is still virtually unconstrained. Adopting the very high value that has been occasionally used in the literature results in the flexion contribution being basically negligible with respect to the shear one, and for realistic configurations the former does not improve significantly the constraining power of the latter. Since the flexion noise decreases with decreasing scale, by extending the analysis up to $\ell_\mathrm{max} = 20,000$ cosmic flexion, while being still subdominant, improves the shear constraints by $\sim 10$ when added. However on such small scales the highly non-linear clustering of matter and the impact of baryonic physics make any error estimation uncertain. By considering lower, and possibly more realistic, values of the flexion intrinsic shape noise results in flexion constraining power being a factor of $\sim 2$ better than that of shear, and the bounds on $\sigma_8$ and $f_\mathrm{NL}$ being improved by a factor of $\sim 3$ upon their combination. (abridged)Comment: 30 pages, 4 figures, 4 tables. To appear on JCA