Optical Networks and Systems Lab.
The Optical Networking laboratory is dedicated to applied and experimental research mainly conducted within the framework of the ADRENALINE testbed ®. By using laboratory facilities, it is possible to evaluate the service levels seen by the client layers of an optical infrastructure of a dynamic Wavelength Switched Optical Network (WSON) in order to obtain meaningful performance data (packet loss, delay, BER). To this end, dedicated broadband testing equipment can be configured to generate and correlate a wide range of optical client interfaces. In the laboratory, there is dedicated Optical Network Test and Measurement equipment, with features such as IP traffic generation and analysis over 10/100 Ethernet, Gigabit Ethernet (GigE), STM-16 and 10GBit interfaces, GMPLS/MPLS network emulation and protocol testing.
Physical layer degradations can be modelled, measured and quantified with Optical Communication Test and Measurement equipment also available, such as a communications signal analyzer (up to 20 GSa/s, 4 GHz bandwidth, with optical and electrical inputs), a digital sampling oscilloscope (up to 13.5 Gbps, 9 GHz/20 GHz for optical/electrical input), an optical spectrum analyzer (with WDM analysis), some tunable laser sources (S, C and L bands), a portable optical time-domain reflectometer (OTDR, for 1310 nm and 1550 nm), a lightwave multimeter (with optical attenuator and high power sensor modules), some optical power meters (for 1300, 1310, 1490, and 1550 nm), a polarization scrambler, PMD and CD analyzers, a broadband source (C and L bands) useful as a PMD/CD analyzer source and a fixed PMD emulator. Belonging to this category, there is additional equipment in the laboratory intended for the development of an Experimental platform for Optical OFDM Systems (EOS), within the ADRENALINE testbed ®: on one hand, an arbitrary waveform generator (up to 24 GSa/s and 9.6 GHz) provides an analog signal (from a digital one) to be modulated and transmitted on an optical link; on the other hand, with a real-time digital phosphor oscilloscope (up to 100 GSa/s, 20 GHz bandwidth) placed on the reception side, the photo-detected signal is electrically captured, sampled and post-processed. EOS platform also integrates several optical, electro-optical and electrical devices necessary to implement both the transmitter and receiver: a LiNbO3 Mach-Zehnder modulator (MZM) with a RF driver (both up to 40 GHz) to generate the optical signal from the analog electrical one; a PIN photo-detector (50 GHz bandwidth, loaded with 50 Ω) with external RF amplifier (24 dB of Gain, up to 20 GHz) to photo-detect the received optical signal and to adapt its power prior to sampling by the oscilloscope (direct detection schemes, DD). By using additional devices also available, such as, double-balanced mixers (IF up to 10 GHz, LO/RF from 9 to 20 GHz), a power splitter (up to 18 GHz) and a voltage controlled oscillator (VCO, up to 20 GHz), it is possible to implement up-conversion/down-conversion stages within the transmitter/receiver respectively.
Design, Development and assembly of Hardware for new opto-electronic subsystems is possible thanks to several facilities such as, for example, printed circuit board (PCB) designer software, FPGA simulation and synthesis software, dual and triple DC Power Supplies, a multimeter, and other devices that are accessible thanks to the support of the Engineering Unit laboratory: soldering irons, microscopes, a circuit board plotter suitable for producing PCB prototypes, a natural convection oven for drying and sterilizing and a CeNeCe milling machine suitable for making front and rear panels of prototypes. Moreover, the floor of the Optical Networking laboratory is certified with an electrostatic behaviour of Conductive, so it drains electrostatic charges deposited on it to ground, in order to avoid electrostatic discharge when handling hardware components.
Optical Passive Components and Fiber-Optic Inspection devices are also suitable for making measurements and experiments that involve the use of Test and Measurement equipment or Hardware Design and Development facilities, and for the EOS platform development: a mini video microscope with camera and TFT display can be found, also a precision fiber cleaver, or several fiber-optic adapters (simplex and duplex, for different kinds of connectors), attenuators (different kinds, from 1 to 15 dB), and several fiber-optic patch cords (3, 5 or 10 m, also terminated with different kinds of connectors). Furthermore, standard G652 SM fiber-optic spools are available (10, 25 and 50 Km, all with 0.19 dB/Km of attenuation), in order to evaluate the transmission over different distances. In the same way, several RF Components are also available: 50Ω cable assemblies with different lengths (up to 1.5 m), material characteristics (hand-formable, semi-rigid or flexible), frequency range (from DC to 12.4, 13, 18 or 26.5 GHz), and with different terminations (SMA, SMP, etc.). There are also several RF adapters (SMA, V or K interfaces), attenuators (from 3 to 20 dB, with frequency range either up to 18 GHz or up to 26 GHz), loads (50 Ω), DC-blocks and different low-pass filters (from DC to either 5 GHz or 7.2 GHz). Additionally, test and measurement cables (red and black with different terminations) can be used for providing electrical connections throughout the experiments. Different types of components for grounding provide ESD protection: a grounding mat, adjustable wriststrap sets, heel grounders and Earth bonding plugs.
VPI Systems and Matlab Simulation tools are available for the design and analysis of optical transmission systems, by means of reliable models of the electrical and optical basic modules (e.g. transmitters, modulators, receivers, amplifiers, filters, fibers), or for the design and characterization of optical amplifiers or active and passive photonics devices, for optical signal processing and investigation on integrated components. OPNET tools are usable for the design and analysis of different communication networks, devices, protocols and applications. There are hundreds of protocols and vendor device models with source code included.
Software developments and applications are developed on the requirements of researchers. The software development team has strong knowledge of C/C++ (C99 / c++11), including standard, Boost and Qt libraries, proved by the expertise in developing GNU/Linux system and applications. Software development team also uses Perl, Python and Java. The servers include all necessary services for software development: bugtracking, version control (subversion), Fully Automated Linux, drupal and phpBB for web-based services. Several development methodologies have been successfully applied, such as waterfall, V-Model or Agile.