Strong experimental guarantees in ultrafast quantum random number generation

We describe a methodology and standard of proof for experimental claims of quantum random number generation (QRNG), analogous to well-established methods from precision measurement. For appropriately constructed physical implementations, lower bounds on the quantum contribution to the average min-entropy can be derived from measurements on the QRNG output. Given these bounds, randomness extractors allow generation of nearly perfect "{\epsilon}-random" bit streams. An analysis of experimental uncertainties then gives experimentally derived confidence levels on the {\epsilon} randomness of these sequences. We demonstrate the methodology by application to phase-diffusion QRNG, driven by spontaneous emission as a trusted randomness source. All other factors, including classical phase noise, amplitude fluctuations, digitization errors and correlations due to finite detection bandwidth, are treated with paranoid caution, i.e., assuming the worst possible behaviors consistent with observations. A data-constrained numerical optimization of the distribution of untrusted parameters is used to lower bound the average min-entropy. Under this paranoid analysis, the QRNG remains efficient, generating at least 2.3 quantum random bits per symbol with 8-bit digitization and at least 0.83 quantum random bits per symbol with binary digitization, at a confidence level of 0.99993. The result demonstrates ultrafast QRNG with strong experimental guarantees.Comment: 11 pages, 9 figure

Sistemas ópticos con multiplexación por división en código (OCDMA) empleando redes de difracción de Bragg sobre fibra óptica

Los avances de los últimos años en dispositivos ópticos han permitido que las tecnologías de codificación y decodificación óptica sean hoy en día una realidad. Existen múltiples aplicaciones en las que es posible utilizar los procesos de cod/decodificación óptica, pero la más conocida es el acceso múltiple por división en código dentro de un entorno óptico, conocida como OCDMA por sus siglas en ingles. En esta tesis doctoral se presenta un estudio de los sistemas OCDMA de tipo coherente, abarcando dos aspectos fundamentales; el modelado del ruido que interfiere con la señal objetivo y el diseño e implementación de las redes de difracción de Bragg como dispositivos Cod/decodificadores. Dentro del modelado del ruido se han incluido la mayor cantidad de variables posibles, con el objeto de conseguir un modelo lo más acertado posible. De esta manera, se considera desde el ancho de banda del receptor hasta el estado de polarización de las señales, pasando por el uso de los dos tipos de modulación más importantes en estos sistemas, como son OOK (On-Off Keying) y DPSK (Differential Phase Shift Keying). Por otra parte, las redes de difracción de Bragg se presentan como los dispositivos más prometedores para ser usados en OCDMA, gracias a su versatilidad y a estar construidas sobre fibras ópticas. Por ello se ha dedicado especial atención a estudiar sus características, destacando en especial, su dependencia con la temperatura y la relevancia de la reflectividad sobre su comportamiento al cod/decodificar señales. A partir de allí se presenta un novedoso método de diseño, realizado mediante un proceso de síntesis, que da como resultado un dispositivo con excelentes prestaciones. En esta tesis también se estudia la codificación y decodificación todo óptica de etiquetas en redes de conmutación de paquetes. Esta aplicación busca reducir los tiempos de proceso que se tienen en la actualidad en un nodo óptico y ha sido propuesta hace ya un par de años. Aquí nos enfocamos en dos asAmaya Ocampo, WA. (2008). Sistemas ópticos con multiplexación por división en código (OCDMA) empleando redes de difracción de Bragg sobre fibra óptica [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/3788Palanci

Super-structured Fiber Bragg Gratings with improved features for Coherent Direct Sequence OCDMA

[EN] This paper reports different proposals in the field of the Super-structured Fiber Bragg Gratings for Coherent Direct Sequence OCDMA applications providing enhanced fea- tures in terms of available spectral bandwidth, spectral efficiency and inter-channel rejection suitable for WDM and OCDMA combined applications. The reported de- vices cover the multiband en-decoders covering different bands on the same device, the almost rectangular envelope en-decoders demonstrated for both 1 and 5 ITU- 100GHz bands providing flat response and a roll-off better than 5 dB/GHz, and finally a multidimensional WDM/CODE/SPACE multiplexing proposal based on the concatenation of rectangular SSFBGs.This work was supported by the Spanish Government project TEC 2009-12169, and the Valencian Government under the project ACOMP/2010/023.Baños López, R.; Pastor Abellán, D.; García Muñoz, V.; Amaya Ocampo, WA. (2013). Super-structured Fiber Bragg Gratings with improved features for Coherent Direct Sequence OCDMA. Waves. 5(1):5-12. http://hdl.handle.net/10251/57917S5125

Modelado de un Sistema de Acceso Múltiple por división de código en el Entorno Óptico

This paper describes the OCDMA technology (Optical Code Division Multiple Access) focussing on the coherent systems OCDMA. The modelling was done using VPI v7.0 and the results of the simulations are presented. The utility of OCDMA as a control access technology it's demonstrated by the simulations which describe the most important aspect to be considered to evaluate the performance of coherent OCDMA Systems.Este documento describe la tecnología OCDMA (optical code division multiple access) centrándose en los sistemas coherentes OCDMA. Se realiza el modelamiento del sistema usando VPI v7.0 y se presentan los resultados de las simulaciones realizadas.Las simulaciones muestran la funcionalidad de OCDMA como tecnología de control de acceso y describe los principales aspectos a tener en cuenta al momento de evaluar el rendimiento de este tipo de tecnología

Dispersion supported BB84 quantum key distribution using phase modulated light

We propose and experimentally demonstrate that, contrary to what was thought up to now, an efficient BB84 operation is feasible using the double phase modulator (PMPM) configuration in frequency-coded quantum key distribution systems without dispersion compensation. This is achieved by exploiting the chromatic dispersion provided by the fiber linking Alice and Bob. Thus, we refer to this system as dispersion supported or as the DS BB84 PMPM configuration. © 2011 IEEE.Mora Almerich, J.; Ruiz Alba Gaya, A.; Amaya Ocampo, WA.; Capmany Francoy, J. (2011). Dispersion supported BB84 quantum key distribution using phase modulated light. IEEE Photonics Journal. 3(3):433-440. doi:10.1109/JPHOT.2011.2146764S4334403

Análisis del Problema del Ruido en Sistemas TS-OCDMA Coherentes

This paper descibes the analysis related to the noise problems that exist in the TS-OCDMA Systems (Time Spreading - Optical Code Division Multiple Access). This noise is composed by the Beat Noise, Multiple Access Interference Noise, thermal and Shot Noise of the electronics devices presents in the detection process. The model of noise in this paper is evaluated through simulations in which the main parameters to be considered are the power penalty, the BER and the crosstalk.El presente artículo describe el análisis del problema del ruido en los sistemas TS-OCDMA (Time Spreading - Optical Code Division Multiple Access). El ruido total en este tipo de sistemas esta compuesto por ruido de batido, ruido de interferencia de múltiple acceso (MAI) y por el ruido térmico y shot propios de los elementos electrónicos presentes en el proceso de detección. El modelo de ruido que se plantea en este artículo es evaluado mediante simulaciones en donde los principales parámetros a considerar son la penalización de potencia, la razón de error bit (BER) y la diafonía

Chromatic dispersion compensation and coherent Direct-Sequence OCDMA operation on a single super structured FBG

This paper was published in OPTICS EXPRESS 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/OE.20.013966 . Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under lawWe have proposed, fabricated and demonstrated experimentally a set of Coherent Direct Sequence-OCDMA en/decoders based on Super Structured Fiber Bragg Gratings (SSFBGs) which are able to compensate the fiber chromatic dispersion at the same time that they perform the en/decoding task. The proposed devices avoid the use of additional dispersion compensation stages reducing system complexity and losses. This performance was evaluated for 5.4, 11.4 and 16.8 km of SSMF. The twofold performance was verified in Low Reflectivity regime employing only one GVD compensating device at decoder or sharing out the function between encoder and decoder devices. Shared functionality requires shorter SSFBGs designs and also provides added flexibility to the optical network design. Moreover, dispersion compensated en/decoders were also designed into the High Reflectivity regime employing synthesis methods achieving more than 9 dB reduction of insertion loss for each device. © 2012 Optical Society of America.This work was supported by the Spanish Government project TEC 2009-12169, and the Valencian Government under the projects ACOMP/2012/023 and FPA/2012/009.Baños López, R.; Pastor Abellán, D.; Amaya Ocampo, WA.; García Muñoz, V. (2012). Chromatic dispersion compensation and coherent Direct-Sequence OCDMA operation on a single super structured FBG. Optics Express. 20(13):13966-13976. doi:10.1364/OE.20.013966S13966139762013Kitayama, K., Xu Wang, & Naoya Wada. (2006). OCDMA over WDM PON-solution path to gigabit-symmetric FTTH. Journal of Lightwave Technology, 24(4), 1654-1662. doi:10.1109/jlt.2006.871030Xu Wang, & Naoya Wada. (2006). Experimental demonstration of OCDMA traffic over optical packet switching network with hybrid PLC and SSFBG en/decoders. Journal of Lightwave Technology, 24(8), 3012-3020. doi:10.1109/jlt.2006.878287Sotobayashi, H., Chujo, W., & Kitayama, K. (2002). Transparent virtual optical code/wavelength path network. IEEE Journal of Selected Topics in Quantum Electronics, 8(3), 699-704. doi:10.1109/jstqe.2002.1016375Pastor, D., Amaya, W., García-Olcina, R., & Sales, S. (2007). Coherent direct sequence optical code multiple access encoding-decoding efficiency versus wavelength detuning. Optics Letters, 32(13), 1896. doi:10.1364/ol.32.001896Wang, X., Matsushima, K., Nishiki, A., Wada, N., & Kitayama, K. (2004). High reflectivity superstructured FBG for coherent optical code generation and recognition. Optics Express, 12(22), 5457. doi:10.1364/opex.12.005457Pastor, D., Amaya, W., & Garcia-Olcina, R. (2007). Design of high reflectivity superstructured FBG for coherent OCDMA employing synthesis approach. Electronics Letters, 43(15), 824. doi:10.1049/el:20071171Skaar, J., Ligang Wang, & Erdogan, T. (2001). On the synthesis of fiber Bragg gratings by layer peeling. IEEE Journal of Quantum Electronics, 37(2), 165-173. doi:10.1109/3.903065Amaya, W., Pastor, D., Baños, R., & Garcia-Munoz, V. (2011). WDM-Coherent OCDMA over one single device based on short chip Super structured fiber Bragg gratings. Optics Express, 19(24), 24627. doi:10.1364/oe.19.024627Amaya, W., Pastor, D., & Capmany, J. (2008). Modeling of a Time-Spreading OCDMA System Including Nonperfect Time Gating, Optical Thresholding, and Fully Asynchronous Signal/Interference Overlapping. Journal of Lightwave Technology, 26(7), 768-776. doi:10.1109/jlt.2007.91520