High-capacity 5G fronthaul networks based on optical space division multiplexing

\u3cp\u3eThe introduction of 5G mobile networks, bringing multi-Gbit/s user data rates and reduced latency, opens new opportunities for media generation, transport and distribution, as well as for new immersive media applications. The expected use of millimeter-wave carriers and the strong network densification resulting from a much reduced cell size--which enable the expected performance of 5G--pose major challenges to the fronthaul network. Space division multiplexing (SDM) in the optical domain has been suggested for ultra-high capacity fronthaul networks that naturally support different classes of fronthaul traffic and further enable the use of analog radio-over-fiber and advanced technologies, such as optical beamforming. This paper discusses the introduction of SDM with multi-core fibers in the fronthaul network as suggested by the blueSPACE project, regarding both digitized and analog radio-over-fiber fronthaul transport as well as the introduction of optical beamforming for high-capacity millimeter-wave radio access. Analog and digitized radio-over-fiber are discussed in a scenario featuring parallel fronthaul for different radio access technologies, showcasing their differences and potential when combined with SDM.\u3c/p\u3

Simplified model enabling optimization of silicon modulators

International audienceIn this work, the simplified modeling of silicon phase modulators is presented along with a comparison among different options of modulators. The proposed simplified model enables a substantial reduce in computational effort while maintaining a good accuracy. The presented model is validated against complete 3D-simulations by means of the design of four different modulators. Furthermore, with the help of the model a deep insight on the performances tradeoffs in the choose and design of silicon modulators is provided

Engineering the optical properties of silicon using sub-wavelength structures

In most integrated optics platforms, including silicon-on-insulator, only minor modifications in refractive index are possible. The geometry of the waveguiding structure is thus the only degree of freedom for the design of devices. The use of sub-wavelength gratings (SWGs), i.e. structures that are small enough to suppress diffraction effects, enables local engineering of both refractive index and dispersion, thereby opening new possibilities for device design. Here we present some of the recent advances in refractive index and dispersion engineering using silicon SWGs, focussing on ultra-broadband and compact multimode interference couplers and directional couplersThis work was supported by the Spanish Ministerio de Ciencia (project TEC2009-10152), the European Mirthe project (FP7-2010-257980), and the Universidad de Málaga - Campus de Excelencia Internacional Andalucìa Tech

Re-inventing Multimode Interference Couplers Using Subwavelength Gratings

We use the concept of subwavelength grating (SWG) refractive-index-engineering to propose and experimentally demonstrate a reduced size, slotted 2x2 MMI coupler. We also present an ultra-broadband 2x2 MMI coupler which is based on SWG dispersion engineering.This work was supported in part by the Spanish Ministerio de Ciencia (project TEC2009-10152), a Formación del Profesorado Universitario scholarship (AP-2006-03355), the European Mirthe project (FP7-2010-257980) and “Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Polarization management for coherent optical receivers

The constant growth of bandwidth requirements in optical communication networks has prompted the evolution from conventional on-off-keying (OOK) transmission techniques to coherent, polarization multiplexed schemes. The higher spectral efficiency afforded by this approach enables per channel data rates of 100–400Gbps over existing fiber infrastructure. Both the transmitters and receivers benefit from monolithic integration, as it reduces costs and offers rugged performance. A block diagram of a coherent polarization multiplex receiver is shown in Fig. 1(a) and basically consists of: i) polarization splitters ii) high performance 90º hybrids and iii) high speed photodiodes. A first monolithically integrated coherent receiver was presented in [1], which, however, required external polarization management. Integration of the polarization managing elements, such as polarization splitters or polarization rotators, is challenging as they exhibit stringing fabrication tolerances. Here, we will review some recent advances in integrated polarization management. Furthermore, we discuss the design of tunable, fabrication tolerant polarization splitters based on Mach-Zehnder structures as shown in Fig. 1(b) [2], carried out in the EU-FP7 Mirthe project. The operation of a monolithically integrated polarization multiplex coherent receiver based on these polarization splitters has been recently demonstrated [3].Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Subwavelength metamaterial structures for silicon photonics

Sub-wavelength periodic metamaterial structures are enabling the design of silicon photonic devices with unprecedented performance in the near infrared band. However, for applications in the promising mid-infrared band it is expected that they acquire even more prominence because for longer wavelengths it is far easier to fabricate structures with a sub- wavelength pitch. Here we report our recent progress in the electromagnetic modeling of sub-wavelength structures, and we will review some of our latest advances in the development of sub-wavelength based devices operating both at near and mid- infrared wavelengths.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

High-capacity 5G fronthaul networks based on optical space division multiplexing

The introduction of 5G mobile networks, bringing multi-Gbit/s user data rates and reduced latency, opens new opportunities for media generation, transport and distribution, as well as for new immersive media applications. The expected use of millimeter-wave carriers and the strong network densification resulting from a much reduced cell size--which enable the expected performance of 5G--pose major challenges to the fronthaul network. Space division multiplexing (SDM) in the optical domain has been suggested for ultra-high capacity fronthaul networks that naturally support different classes of fronthaul traffic and further enable the use of analog radio-over-fiber and advanced technologies, such as optical beamforming. This paper discusses the introduction of SDM with multi-core fibers in the fronthaul network as suggested by the blueSPACE project, regarding both digitized and analog radio-over-fiber fronthaul transport as well as the introduction of optical beamforming for high-capacity millimeter-wave radio access. Analog and digitized radio-over-fiber are discussed in a scenario featuring parallel fronthaul for different radio access technologies, showcasing their differences and potential when combined with SDM

Novel compact transmitters for short-reach optical communication

International audienceIn this talk, we will review our recent work on the demonstration of novel compact transmitter structures employing Si or III-V integration for short reach optical communications. A special focus will be given on means to address the limitations induced by group-velocity dispersion for such systems. Customized modulators operating in the O-band, or employing single-sideband modulation in conjunction with single- (PAM2 and PAM4) or multi-carrier (OFDM) modulation in the C-band will be presented