Photonic integration enabling new multiplexing concepts in optical board-to-board and rack-to-rack interconnects

New broadband applications are causing the datacenters to proliferate, raising the bar for higher interconnection speeds. So far, optical board-to-board and rack-to-rack interconnects relied primarily on low-cost commodity optical components assembled in a single package. Although this concept proved successful in the first generations of optical-interconnect modules, scalability is a daunting issue as signaling rates extend beyond 25 Gb/s. In this paper we present our work towards the development of two technology platforms for migration beyond Infiniband enhanced data rate (EDR), introducing new concepts in board-to-board and rack-to-rack interconnects. The first platform is developed in the framework of MIRAGE European project and relies on proven VCSEL technology, exploiting the inherent cost, yield, reliability and power consumption advantages of VCSELs. Wavelength multiplexing, PAM-4 modulation and multi-core fiber (MCF) multiplexing are introduced by combining VCSELs with integrated Si and glass photonics as well as BiCMOS electronics. An in-plane MCF-to-SOI interface is demonstrated, allowing coupling from the MCF cores to 340x400 nm Si waveguides. Development of a low-power VCSEL driver with integrated feed-forward equalizer is reported, allowing PAM-4 modulation of a bandwidth-limited VCSEL beyond 25 Gbaud. The second platform, developed within the frames of the European project PHOXTROT, considers the use of modulation formats of increased complexity in the context of optical interconnects. Powered by the evolution of DSP technology and towards an integration path between inter and intra datacenter traffic, this platform investigates optical interconnection system concepts capable to support 16QAM 40GBd data traffic, exploiting the advancements of silicon and polymer technologies

Photonic Provisioning Using a Packaged SOI Hybrid All-Optical Wavelength Converter in a Meshed Optical Network Testbed

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Chapter Merging Plasmonics and Silicon Photonics Towards Greener and Faster “Network-on-Chip” Solutions for Data Centers and High-Performance Computing Systems

Endocrinolog

Merging Plasmonics and Silicon Photonics Towards Greener and Faster “Network-on-Chip” Solutions for Data Centers and High-Performance Computing Systems

Endocrinolog

Σχεδιασμός και Προσομοίωση Οπτικού Δικτύου Πρόσβασης για Παροχή Πολλαπλών Ευρυζωνικών Υπηρεσιών

156 σ.Στα πλαίσια της παρούσας διπλωματικής εργασίας σχεδιάζεται και μελετάται μια αρχιτεκτονική ενός ευρυζωνικού δικτύου πρόσβασης, το οποίο λειτουργεί πάνω από οπτική ίνα. Πιο συγκεκριμένα εξετάζουμε τη δυνατότητα παροχής τριών υπηρεσιών, σε ένα χρήστη, πάνω από ένα μήκος κύματος, βασιζόμενοι σε μια λογική δομής πομπού και δέκτη, αλλά, κατα κύριο λόγο, κεντρικοποιημένη ως προς τον πομπό. Η μετάδοση των υπηρεσιών αποτελεί υλοποίηση ενός Radio over Fiber συστήματος καθώς, η μια υπηρεσία αφορά ενσύρματη διασύνδεση που προσφερει ρυμθό μετάδοσης 1244Mbps, και οι άλλες δύο είναι ασύρματες με ρυθμό μετάδοσης 622Mbps. Οι ασύρματες υπηρεσίες είναι δύο καθώς διευρευνουμε τη δυνατότητα μετάδοσης τόσο σε κλασσικές και ήδη αξιοποιημένες συχνοτικές ζώνες, όπως τα 5GHz, οσο και σε φασματικές περιοχες πολύ πιο υψηλές που αποτελούν το επόμενο βήμα στις ασύρματες και προσωπικές επικοινωνίες, όπως είναι η περιοχή των 60GHz. Για να επιτευχθεί η μετάδοση και των τριών αυτών υπηρεσιών, ο πομπός του κυκλωματος σχεδιάσθηκε έτσι ώστε να πραγματοποιεί διαμόρφωση με υποφέρουσες (SubCarrier Multiplexing, SCM) του οπτικού σηματος, μια τεχνική που επιτρέπει τη μετάδοση πολλών διαφορετικών καναλιών πάνω από ένα οπτικό φέρον, ενώ χρησιμοποιήθηκε ένας Mach – Zehnder διαμορφωτής. Για τη λήψη των σημάτων χρησιμοποιήθηκαν δύο διαφορετικές τεχνικές, ανάλογα με το αν επρόκειτο για ενσύρματη ή για ασύρματη διασύνδεση. Έτσι ο δέκτης του ενσύρματου καναλιού βασίστηκε στην απ'ευθείας ανίχνευση (Direct Detection), ενώ οι δέκτες των ασύρματων καναλιών αξιοποιούσαν τις αρχές της ετερόδυνης αποδιαμόρφωσης (Remote Heterodyne Detection, RHD), που επιτρέπει τη δημιουργία υψίσυχνων ηλεκτρικών σημάτων κατα την οπτικο – ηλεκτρική μετατροπή. Κατα τη διάρκεια των προσομοιώσεων καταδεικνύουμε τη λειτουργία του κυκλώματος, βάσει των προδιαγραφών που έχουν τεθεί, ενώ εξετάζουμε και την ποιότητα τις επικοινωνίας που αυτό παρέχει, εξετάζοντας συγκεκριμένες παραμέτρους και παρουσιάζοντας σε κάθε περίπτωση στοιχεία σχετικά με τα λαμβανόμενα BER και Q. Στο τέλος της εργασίας μελετάται η δυνατότητα επέκτασης της αρχιτεκτονικής, ούτως ώστε να πραγματοποιηθεί μετάδοση τουλάχιστον 14 υπηρεσιών πάνω από ένα μήκος κύματος σε ένα χρήστη, χωρίς να γίνουν σημαντικές αλλαγές στη δομή του σχεδιασμένου κυκλώματος. Η σχεδίαση του κυκλώματος, καθώς και οι προσομοιώσεις γίνονται με τη βοήθεια του εξειδικευμένου λογισμικού προσομοίωσης οπτικών κυκλωμάτων.The purpose of this thesis is to examine and develop the architecture of a broadband access network, that operates over optical fiber. In particular, it deals with the concept of providing three services to a user, over a single wavelength. The design is based on a server – client structure, which is mainly centralized to the server, who is, more correctly, characterized as “central station”. In order to realize the transmission of the signals that correspond to the services, we exploit the principles of the Radio – over – Fiber technology, in such a way that two wireless and one LAN signal are being transmitted. The wireless signals provide a BitRate of 622Mbps, while the BitRate of the LAN is double. We have comprised two wireless services, because we want to research the possibility to use the architecture not only for the transmission of Super High Frequencies (SHF), like WLAN, but also for the transmission of Extremely High Frequencies (EHF), which will be the frequency range of future wireless communications, like WPAN. In order to achieve instantaneous transmission of the three services, it has been decided to use SubCarrier Multiplexing (SCM) at the central station, in order to modulate the optical signal in a way that would cause the appearance and transmission of pre – modulated SubCarriers along with the optical Carrier. This can be done by using a Mach – Zehnder Modulator, like the one that is used in the thesis. The reception of the signals was carried out in two different ways, depending on the nature of each one of them. The LAN signal is being received with Direct Detection, which is the simplest method to demodulate optical signals, while the wireless ones are being received with Remote Heterodyne Detection, which is quite more complicated, but eventually it can be used to produce high frequency radio signals. During the simulation we demonstrate the feasibility of the architecture according to the specifications, and, at the same time we evaluate the quality of the communication, by performing measurements of certain quantities, like Bit Error Rate (BER) and Q. Finally we examine the potential of upgrading the architecture in order to include more services, without changing the basic structure. The construction of the optical circuit, as well as the simulation, was realized by using VPI Transmission Maker, which is a very powerful software that accelerates the design of new photonic systems.Δημήτριος Ι. Καλαβρουζιώτη

Wastewater Reuse Planning in Agriculture: The Case of Aitoloakarnania, Western Greece

In the present paper, the possibility of the treated municipal wastewater (TMWW) reuse in agriculture, produced by the Wastewater Treatment Plants of Aitoloakarnania prefecture, one of the greatest agricultural regions of Greece, has been investigated. The boundaries of agricultural soils and the irrigated crops were defined, and the water requirements of crops were calculated. Also the chemical characteristics of the TMWW were determined for the safe reuse in crop production, and for the protection of soils from potential pollution. The research conducted in this area is expected to constitute the basis for an integrated TMWW reuse planning in soils and crops, in the context of sustainable agriculture, and environmental protection. It must be mentioned that the Messolongion-Aitolikon lagoon is in the area under investigation, one of the largest wetland ecosystem of Mediterranean region, which makes the area ecologically sensitive. The ultimate scope of this study is to describe the planning of the TMWW reuse on the basis of soil characteristics, climatic factors, and irrigation water requirements of the crops, grown in this ecologically sensitive area. The volume of the effluents produced by the wastewater treatment plants of Messolonghion, Agrinion, Nafpaktos, Aitoliko and Thermo could cover 19.3%, 25.14%, >100%, 17.18 and 87.84% of the irrigation water requirements, respectively

pH and organicmatter impact on the indices of soil metal load assessment under wastewater and biosolid reuse

Backgound: Experimental data were used to study the impact of pH and organic matter on soil pollution indices, with the view to express them as a function of the above two variables. Results: Data were from an experiment performed in a greenhouse using 12 wastewater and sludge treatment combinations in four replications, using Lactuca sative var Longifolia as a test plant. The experimental data were analyzed by means of linear multiple regression analysis, and the equations found were considered as revised forms for the calculation of pollution indices, which could be used as a tool for the assessment of the level of soil pollution by heavy metals. Conclusion: Tentative critical levels of the pollution indices were established on the basis of the reference revised Index PLIn. However, additional work is necessary, such as calibration of the revised indices on the basis of percentage crop yield loss, towards a more accurate assessment of the heavy metal soil pollution levels