Search results for "Telecommunication"

Advanced Optical Processing of Microwave Signals

2005

The authors present a review on the recent approaches proposed to implement transversal RF filters. Different tunable transversal filters consisting of wavelength tunable optical taps and those employing the tunability of dispersive devices are presented showing their high-performance characteristics. A comprehensive review of the fundamentals and a discussion on the main limitation of these structures are also included.

Plastic optical fibers for transmission and sensors

2005

This paper presents state and ways of development of plastic optical fibers (POF) for use in transmission-measuring devices for small area object networks (LAN networks in stationary and dynamic objects). Transmission links (with new fiber optics, simple optical components -- optical transmitters/receivers) allows nowadays transmission speed of a few Gb/s for a distance of hundreds meters. Properties and advantages of solutions based on plastic optical fiber for control, communication and managing are shown. Example practical solutions, regarding entering new standards and technologies, presents technical and economical advantages, compared to difficult and unfortunately expensive technolog…

All-optical measurements of background, amplitude, and timing jitters for high speed pulse trains or PRBS sequences using autocorrelation function

2008

International audience; We present a simple method for all-optical measurements of background, amplitude, and timing jitters of ultra high speed pulse trains or PRBS sequences using the jitter dependence of the intercorrelation-peak shape. This method is numerically and experimentally demonstrated on a 42.66 Gbit/s PRBS sequence and then applied to measure the jitter growths occurring during the propagation of a 160-GHz pulse train in a classical SMF/DCF dispersion map.

Multiple four-wave mixing in optical fibers: 1.5–3.4-THz femtosecond pulse sources and real-time monitoring of a 20-GHz picosecond source

2010

International audience; In this work, we report recent progress on the design of all-fibered ultra-high repetition-rate pulse sources for telecommunication applications around 1550 nm. The sources are based on the non-linear compression of an initial beat-signal through a multiple four-wave mixing process taking place into an optical fiber. We experimentally demonstrate real-time monitoring of a 20 GHz pulse source having an integrated phase noise 0.01 radian by phase locking the initial beat note against a reference RF oscillator. Based on this technique, we also experimentally demonstrate a well-separated high-quality 110 fs pulse source having a repetition rate of 2 THz. Finally, we show…

Peregrine soliton generation and breakup in standard telecommunications fiber

2011

International audience; We present experimental and numerical results showing the generation and breakup of the Peregrine soliton in standard telecommunications fiber. The impact of non-ideal initial conditions is studied through direct cut back measurements of the longitudinal evolution of the emerging soliton dynamics, and is shown to be associated with the splitting of the Peregrine soliton into two subpulses, with each subpulse itself exhibiting Peregrine soliton characteristics. Experimental results are in good agreement with simulations.

Measured and predicted light attenuation in dense coastal upslope fog at 650, 850, and <inline-formula><math display="inline" overflow="scro…

2008

Free-space optics FSO has gained considerable importance in this decade of demand for high-bandwidth transmission capabilities. FSO can provide the last mile solution, but the availability and reliability issues concerned with it have received increasing attention and need thorough investigation. In this work, we present our results on fog attenu- ation measurement and prediction at wavelengths 650, 850, and 950 nm with peak values up to 500 dB/km. For the attenuation measurement, optical wavelengths are transmitted over the same path of fog in free air to a receiver, measuring the power at every wavelength. The measure- ment of fog attenuation was performed at the France Telecom RD free-sp…

Efficient photo-thermal activation of gold nanoparticle-doped polymer plasmonic switches

2012

International audience; We report on the photo-thermal activation of dielectric loaded plasmonic switches comprised of gold nanoparticle-doped polymer deposited onto a gold film. The plasmonic switches rely on a multi-mode interferometer design and are fabricated by electron beam lithography applied to a positive resin doped with gold nanoparticles at a volume ratio of 0.52%. A cross-bar switching is obtained at telecom wavelengths by pumping the devices with a visible beam having a frequency within the localized surface plasmon resonance band of the embedded nanoparticles. By comparing the switching performances of doped and undoped devices, we show that for the modest doping level we cons…

Backscatter and Transmission through a Lead Shield Used in Surface and Interstitial HDR Brachytherapy

2014

Automatic EMI filter design for power electronic converters oriented to high power density

2018

In this paper, a complete computer aided procedure based on the power density concept and aimed at the automatic design of EMI filters for power electronic converters is presented. It is rule-based, and it uses suitable databases built-up by considering information on passive components available from commercial datasheets. The power density constraint is taken into consideration by imposing the minimization of the filter volume and/or weight; nevertheless, the system in which the automatically designed filter is included satisfies the electromagnetic compatibility standards limits. Experimental validations of the proposed procedure are presented for two real case studies, for which the per…

On the optimal design of multi-stage cascaded transistor amplifiers with noise, gain and mismatch constraints

2007

The problem of evaluating the optimal performances of cascaded, unbalanced, multi-stage transistor amplifiers is addressed. In particular, a theoretically rigorous approach is proposed for the determination of a family of Optimal Design Curves (ODC's) which express the best noise-gain tradeoff that can be achieved - at each frequency and device operating condition - when a simultaneous constraint on amplifier input VSWR is accounted for. Such curves can be used as a more meaningful starting point in practical amplifier design in place of the approximate calculations so far employed for target performance or optimization goals determination.