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Digital Optical Transmission Systems Print

The application notes listed below are the result of the Joint Experimental Activities performed by the 17 members of EURO-FOS consortium and Network, during the 4 years of the duration of the project. They formulate an extremely useful source of on-hands information and consolidated laboratory know-how to the researchers in the domain of photonics communications.

Contributing Institutions: Acreo in cooperation with Finisar and Ericsson
Summary: In this application note we are going to describe the experimental method used at Acreo Netlab for characterization of laser phase noise.  The method is based on measurements of' a  mixed output from two lasers operated in continuous wave (CW) by applying an optical front-end coherent receiver with electrical 3dB-bandwidth of 40GHz and 50GS/s real-time scope (sampler). We are also going to describe the measured data analysis that leads to frequency noise power spectral density as well as to effective time-dependent laser linewidth.
 
Contributing Institutions: AIT
Summary: This application note provides the design considerations for the development of a recirculating loop set-up. It also describes the methodology for the correct operation of the set-up for a reference optical link. Finally, the use of the recirculating loop set-up for the evaluation of  optical regeneration schemes is described focusing on three main variations.
 
Contributing Institutions: Karlsruhe Institute of Technology
Summary: In this application note, we give a short introduction on implementing a polarization multiplexing emulator.
 
Contributing Institutions: Politecnico di Torino (PoliTO)
Summary: The Finisar Waveshaper filter is a programmable optical filter, that can in general be configured by the user in order to obtain any desired shape. In the following, we describe the entire process that can be used to generate Nyquist spectra at its output, using the “User Configured Filters”(UCF) operational mode of the instrument. We also provide a sample Matlab file that can be used to generate the filter profile to be input to the instrument.
 
Contributing Institutions: 
Summary: 
 
Contributing Institutions: TUE, DTU
Summary: This is an application note resulting from the JEA 3.16 “Optical packet switching transmission and burst mode detection in ultra-high speed systems”. The objective is to provide a comprehensive guideline of in-band clock distribution and short pulse generation for OTDM systems at data-rates of up to 640 Gb/s. We present here the step by step implementation of a packet clock distribution method that allows for fast locking, low timing jitter and highly stable clock performance. We also describe the technique to compress the extracted clock to generate a 10-GHz 1-ps pulse train that is needed for all-optical time demultiplexing.
 
Contributing Institutions: Fraunhofer Institute for Telecommunications, Heinrich Hertz Institut
Summary: This application note describes how to generate an optical data signal carrying the  modulation format “polarization switched quadrature phase shift keying (PS>QPSK)”and  outlines a simple way to adjust the bias voltages of the modulator. 
 
Contributing Institutions: Fraunhofer Institute for Telecommunications, Heinrich Hertz Institut
Summary: This application note describes how to generate an optical data signal carrying the modulation format “6-ary polarization-shift keying quadrature phase-shift keying  (6PolSK-QPSK)” and outlines a simple way to adjust the bias voltages of the modulator.
 
Contributing Institutions: Fraunhofer Institute for Telecommunications, Heinrich Hertz Institut
Summary: This application note gives a step-by-step tutorial how to perform numerical calculations on Nvidia GPU. It uses the MEX interface of MATLAB, so that time consuming tasks can simply calculate on the GPU directly from within MATLAB. Further a simple example code is provided.
 
Contributing Institutions: Fraunhofer Institute for Telecommunications, Heinrich Hertz Institut
Summary: This application note describes a basic way to communicate with a Le Croy sampling scope in order to get sampled waveforms or to send acquisition commands.
 
Contributing Institutions: Fraunhofer Institute for Telecommunications, Heinrich Hertz Institut
Summary: A software tool for acquiring screen shots and providing useful remote  control functions for Agilents DCA series oscilloscopes is presented.
 
Contributing Institutions: Chalmers, DTU, NTUA, IT
Summary: The feasibility of transmitting 0.87 Tbit/s dual polarization D8PSK-OTDM over 110  km is, for the first time, demonstrated along with 0.44 Tbit/s single polarization D8PSK-OTDM over 220 km in conventional 55-km span SMF+DCF link. The information in this Application Note was also presented and published at ECOC 2010.
 
Contributing Institutions: IMEC, POLITO
Summary: Arbitrary waveform generators (AWGs) are extremely versatile and useful instruments  to generate advanced broadband modulated signals. The digital-to-analog conversion process in AWGs, however, also generates a number of undesired signal components that need to be filtered. This application note introduces the background of this phenomenon and shows how microwave filters can be used to improve the signal-to-noise ratio of digitally generated broadband signals.
 
Contributing Institutions: Chalmers, Institute TELECOM
Summary: The application note gives a practical instruction on the digital signal processing necessary for analysis of coherent signals received in parallel detectors and samplingunits.
 
Contributing Institutions: Karlsruhe Institute of Technology
Summary: Nyquist sinc+pulse shaping provides spectral efficiencies close to the theoretical limit. Here we show that using appropriate algorithms, Nyquist pulse shaped modulation formats can be encoded on a single wavelength at speeds beyond 100 Gbit/s in real+time. Finally, we discuss the proper reception of Nyquist pulses.
 
Contributing Institutions: ICCS/NTUA
Summary: The procedure of setting and operating successfully a QPSK modulator is given. In the introduction the common architecture of a QPSK modulator is presented. Next, a short analysis regarding the operating principle of the device is given. Finally, the process of operating a QPSK modulator is presented in well-described single steps.
 
Contributing Institutions: Politecnico di Torino (PoliTO)
Summary: The AWGs from Tektronix AWG7000B Series can generate two independent output channels at a sampling speed up to 12 Gsamples/s. A special function called “Interleave” is available which allows doubling the sampling speed of the instrument by combining the signals at the two independent outputs. When Interleave is on, the “zeroing” function, which can be turned on or off, allows you to select whether you want to handle each waveform as RZ (Return to Zero) or NRZ (Non Return to Zero). The interleaved output w/o zeroing has the advantage of delivering twice the output voltage than the one with zeroing , however the way input samples has to be generated is not straightforward, thus in this application note we will focus on the description of how to program the Tektronix AWG when using the interleave w/o zeroing function.
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