New opportunities for integrated microwave photonics

Recent advances in photonic integration have propelled microwave photonic technologies to new heights. The ability to interface hybrid material platforms to enhance light-matter interactions has led to the developments of ultra-small and high-bandwidth electro-optic modulators, frequency synthesizers with the lowest noise, and chip signal processors with orders-of-magnitude enhanced spectral resolution. On the other hand, the maturity of high-volume semiconductor processing has finally enabled the complete integration of light sources, modulators, and detectors in a single microwave photonic processor chip and has ushered the creation of a complex signal processor with multi-functionality and reconfigurability similar to their electronic counterparts. Here we review these recent advances and discuss the impact of these new frontiers for short and long term applications in communications and information processing. We also take a look at the future perspectives in the intersection of integrated microwave photonics with other fields including quantum and neuromorphic photonics

Transmission and group-delay characterization of coupled resonator optical waveguides apodized through the longitudinal offset technique

[EN] In this Letter, the amplitude and group delay characteristics of coupled resonator optical waveguides apodized through the longitudinal offset technique are presented. The devices have been fabricated in silicon-on-insulator technology employing deep ultraviolet lithography. The structures analyzed consisted of three racetracks resonators uniform (nonapodized) and apodized with the aforementioned technique, showing a delay of 5 ± 3 ps and 4 ± 0:5 ps over 1.6 and 1:4 nm bandwidths, respectively. © 2011 Optical Society of America.This work has been funded through the Spanish Plan Nacional de I+D+i 2008-2011 project TEC2008-06145/TEC Coupled Resonator Optical Waveguides eNgineering (CROWN). J. D. Domenech acknowledges the Beca de Formacion de Personal Investigador (FPI) research grant BES-2009-018381.Doménech Gómez, JD.; Muñoz Muñoz, P.; Capmany Francoy, J. (2011). Transmission and group-delay characterization of coupled resonator optical waveguides apodized through the longitudinal offset technique. Optics Letters. 36(2):136-138. doi:10.1364/OL.36.000136S136138362Yariv, A., Xu, Y., Lee, R. K., & Scherer, A. (1999). Coupled-resonator optical waveguide:?a proposal and analysis. Optics Letters, 24(11), 711. doi:10.1364/ol.24.000711Poon, J. K. S., Scheuer, J., Xu, Y., & Yariv, A. (2004). Designing coupled-resonator optical waveguide delay lines. Journal of the Optical Society of America B, 21(9), 1665. doi:10.1364/josab.21.001665Poon, J. K., Zhu, L., DeRose, G. A., & Yariv, A. (2006). Transmission and group delay of microring coupled-resonator optical waveguides. Optics Letters, 31(4), 456. doi:10.1364/ol.31.000456Capmany, J., Muñoz, P., Domenech, J. D., & Muriel, M. A. (2007). Apodized coupled resonator waveguides. Optics Express, 15(16), 10196. doi:10.1364/oe.15.010196Xia, F., Rooks, M., Sekaric, L., & Vlasov, Y. (2007). Ultra-compact high order ring resonator filters using submicron silicon photonic wires for on-chip optical interconnects. Optics Express, 15(19), 11934. doi:10.1364/oe.15.011934Domenech, J. D., Muñoz, P., & Capmany, J. (2009). The longitudinal offset technique for apodization of coupled resonator optical waveguide devices: concept and fabrication tolerance analysis. Optics Express, 17(23), 21050. doi:10.1364/oe.17.021050Nanophotonic waveguides in silicon-on-insulator fabricated with CMOS technology. (2005). Journal of Lightwave Technology, 23(1), 401-412. doi:10.1109/jlt.2004.834471Xia, F., Sekaric, L., & Vlasov, Y. A. (2006). Mode conversion losses in silicon-on-insulator photonic wire based racetrack resonators. Optics Express, 14(9), 3872. doi:10.1364/oe.14.003872Taillaert, D., Van Laere, F., Ayre, M., Bogaerts, W., Van Thourhout, D., Bienstman, P., & Baets, R. (2006). Grating Couplers for Coupling between Optical Fibers and Nanophotonic Waveguides. Japanese Journal of Applied Physics, 45(8A), 6071-6077. doi:10.1143/jjap.45.6071Capmany, J., & Muriel, M. A. (1990). A new transfer matrix formalism for the analysis of fiber ring resonators: compound coupled structures for FDMA demultiplexing. Journal of Lightwave Technology, 8(12), 1904-1919. doi:10.1109/50.62888Poon, J., Scheuer, J., Mookherjea, S., Paloczi, G. T., Huang, Y., & Yariv, A. (2004). Matrix analysis of microring coupled-resonator optical waveguides. Optics Express, 12(1), 90. doi:10.1364/opex.12.000090Landobasa, Y. M., Darmawan, S., & Chin, M.-K. (2005). Matrix analysis of 2-D microresonator lattice optical filters. IEEE Journal of Quantum Electronics, 41(11), 1410-1418. doi:10.1109/jqe.2005.85706

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

Design of integrated optics all-optical label swappers for spectral amplitude code label swapping optical packet networks on active/passive InP technology

In this paper the designs of optical label swapper devices, for spectral amplitude coded labels, monolithically integrated on InP active/passive technology are pre sented. The devices are based on cross-gain modulation in a semiconductor optical amplifier. Multi-wavelength operation is enabled by means of arrayed waveguide gratings and ring resonators

Photonic processing of microwave signals

In this paper, recent advances in the implementation of photonic tuneable transversal filters for RF signal processing developed by the Optical Communications Group are described. After a brief introduction to the field and the basic concepts, limiting factors and application of these filters are described in the field. This is based on a distinction between filters based on wavelength tuneable optical taps and others based on the tuneability of the dispersive elements that provide the time delay between samples. Recently developed approaches have also been discussed

Coherent states for continuous spectrum operators with non-normalizable fiducial states

The problem of building coherent states from non-normalizable fiducial states is considered. We propose a way of constructing such coherent states by regularizing the divergence of the fiducial state norm. Then, we successfully apply the formalism to particular cases involving systems with a continuous spectrum: coherent states for the free particle and for the inverted oscillator $(p^2 - x^2)$ are explicitly provided. Similar ideas can be used for other systems having non-normalizable fiducial states.Comment: 17 pages, typos corrected, references adde