• Electromagnetism and Telecommunication Department


Equipment and Ressources

Automated measurement setups of CATV (Community Antenna TeleVision) signals

  • CSO, CTB & CNR measurements
    The setup is formed of programmable equipments with a user-friendly interface : a HP multicarrier generator (100 carriers, including CENELEC42 and PAL), an optical/electrical attenuator and a Rohde & Schwarz spectrum analyzer. FPMs has at his disposal CATV downstream and upstream optical emitters and receivers. The setup is able to measure second and third order distortions (CSO & CTB) as well as noise contribution in TV channels (CNR) following EN50083 standard or with customized parameters. For real CATV signals measurements, FPMs owns a CableTV analyzer
  • QAM & BER measurements
    The setup is based on a Rohde & Schwarz DVB-C/DVB-S Quadrature Amplitude Modulation test modulator/demodulator which are able to generate and analyze QAM constellation parameters and noise performances of a link. This can be coupled with a low bit rate Anritsu Bit Error Rate Tester to analyze error arrival process. A dedicated development has been realized to evaluate an erroneous transmission at the bit level. MPEG-2 Transport Stream analysis is also available.
  • NPR measurements
    An automated Noise Power Ratio measurement setup is available at the FPMs to characterize the non-linear behavior of components and subsystems taking place in liaisons where QAM-like signals are used (large and flat spectrum). The setup is formed of a broadband white noise generator (home-made), a bandpass filter, a notch filter and a Rohde & Schwarz spectrum analyzer. An alternative measurement method, based on RF carriers, has been developed for NPR characterization.

Contact: V. Moeyaert
Bit Error Rate automated measurement setup from 100 Mbit/s up to 3 Gbit/s

FPMs has developed an automated measurement setup around a programmable HP BER meter and a Tektronix CSA. In his actual version (work is going on), the software developed by FPMs allows the capture and the measurement of erroneous bits at a customized rhythm (down to 1 second). From measurement, statistics may be built. Also, by using the BER meter with variable decision threshold and variable time delay, eye diagrams of links can be measured without a classical oscilloscope. This functionality is automated by the software. Individual digital emitters and receivers are available as well as a multirate CWDM platform (max. 2.5 Gbit/s).

Contact: P. Mégret; S. Bette
Distributed measurements of optical fibres parameters

We have developed an experimental bench in order to measure the spatial distribution of fibre parameters for the monitoring of optical fibre links. We are currently capable of measuring the spatial distribution of the polarization mode dispersion, the birefringence and the Raman gain along an optical fibre link. We have, in our lab, an experimental bench that can be easily tailored for various applications of distributed measurements. The main idea of the measurement set-up is to use a commercially available OTDR for the synchronization of pulses launched into the fibre under test and for the detection of the Rayleigh backscattered signal.

Contact: M. Wuilpart
Facilities in optics

The FPMs uses a recent optical research laboratory, controlled in temperature. Major equipments that are available are : - Optical and Electrical spectrum analyzers; - Scanning Fabry Perot; - Autocorrelator; - Vector analyzer; - Analogue and Digital Oscilloscopes (high sampling rates); - Laser metrology facilities (static curve, …); - Writing of fiber Bragg gratings with phase mask and interferometric methods (FABRICAP project);

Contact: M. Wuilpart
Inscription and characterization of Fiber Bragg Gratings (FBG)

FPMs possesses a clean room where FBGs are written owing to an argon laser followed by a frequency doubler and emitting at 244 nm. The transverse holographic technique and the phase/amplitude mask method are implemented in parallel. The first method allows to tune easily the Bragg wavelength of the inscribed grating. The second one is easy to implement and is interesting to write grating with great physical length. Different types of FBGs are written : uniform, compound, superimposed, tilted, apodized, chirped and also long period gratings. During the inscription process, the reflected and transmitted spectra are characterized using a broadband laser source, a circulator and an optical spectrum analyzer. Characterizations are also performed with a tunable laser source and an optical powermeter.

Contact: C. Caucheteur
Actively mode-locked fiber laser soliton source up to 3 Gbit/s

FPMs has developed a harmonic actively mode-locked erbium doped fiber laser source. The source generates transform limited soliton-like pulses with repetition rate up to 3 Gbit/s and duration down to 6 ps. The laser cavity has a sigma shape design allowing the amplifying portion of the laser to be non-polarization maintaining. FPMs has developed an electrical feedback loop driving a piezo-drum that allows a stable operation of the laser toward external conditions variation. Pulse duration can be measured with an autocorrelator. Optical spectrum analyzer, electrical spectrum analyzer and oscilloscope are also available for characterization of the output of the laser. Noise characteristics of the pulse train can be determined with the use of a vector network analyzer.

Contact: P. Mégret