Search results for "Amplifier"
showing 10 items of 239 documents
Comprehensive formulation of the temperature dependent dispersion of optical materials; illustration with the case of temperature tuning of a mid-IR …
2009
International audience; The temperature dependence of refractive indices of optical materials is characterized in this work by what we call their normalized thermo-optic coefficients. These ones are determined experimentally through interferometric measurements of thermal expansion, and changes in optical thickness at a few laser wavelengths as function of temperature. A suitable vectorial formalism applied to these data allows predicting the thermal evolution of the refractive index all over the useful range of transparency. The validity and reliability of our methodology is demonstrated through temperature tuning of a mid-IR HgGa2S4 OPO, pumped at 1.0642 μm by a Nd:YAG laser. Measured the…
APDs as single-photon detectors for visible and near-infrared wavelengths down to Hz rates
2012
For the SPECTRAP experiment at GSI, Germany, detectors with Single-Photon counting capability in the visible and near-infrared regime are required. For the wavelength region up to 1100 nm we investigate the performance of 2x2 mm^2 avalanche photo diodes (APDs) of type S0223 manufactured by Radiation Monitoring Devices. To minimize thermal noise, the APDs are cooled to approximately -170 deg. C using liquid nitrogen. By operating the diodes close to the breakdown voltage it is possible to achieve relative gains in excess of 2x10^4. Custom-made low noise preamplifiers are used to read out the devices. The measurements presented in this paper have been obtained at a relative gain of 2.2x10^4. …
Modulational instability in fiber systems with periodic loss compensation and dispersion management
2003
In this paper we study modulational instability in a Kerr fiber taking into account the combined effects of periodic power variations and dispersion management. It is shown that periodic dispersion management and periodic amplification produce nonconventional MI sidebands which are essentially independent of each other. In addition, we show that the amplifier spontaneous emission noise tends to inhibit the growth of sidebands, for a sufficiently long propagation distance.
The DEPFET based Focal Plane Detectors for MIXS on BepiColombo
2010
X-ray detectors based on arrays of DEPFET macropixels, which consist of a silicon drift detector combined with a detector/amplifier structure DEPFET as readout node, provide a convenient and flexible way to adapt the pixel size of a focal plane detector to the resolving power of any given X-ray optical system. Macropixels combine the traditional benefits of an SDD, like scalability, arbitrary geometry and excellent QE even in the low energy range, with the advantages of DEPFET structures: Charge storage capability, near Fano-limited energy resolution, low power consumption and high speed readout. Being part of the scientific payload of ESA's BepiColombo mission, the MIXS instrument will be …
Self-similarity in ultrafast nonlinear optics
2007
International audience; Recent developments in nonlinear optics have led to the discovery of a new class of ultrashort pulse, the `optical similariton'. Optical similaritons arise when the interaction of nonlinearity, dispersion and gain in a high-power fibre amplifier causes the shape of an arbitrary input pulse to converge asymptotically to a pulse whose shape is self-similar. In comparison with optical solitons, which rely on a delicate balance of nonlinearity and anomalous dispersion and which can become unstable with increasing intensity, similaritons are more robust at high pulse powers. The simplicity and widespread availability of the components needed to build a self-similar amplif…
PESIC: An Integrated Front-End for PET Applications
2007
An ASIC front-end has been developed for multi-anode photomultiplier based nuclear imaging devices. Its architecture has been designed to improve resolution and decrease pile-up probability in Positron Emission Tomography systems which employ continuous scintillator crystals. Analog computation elements are isolated from the photomultiplier by means of a current sensitive preamplifier stage. This allows digitally programmable adjustment of every anode gain, also providing better resolution in gamma event position calculation and a shorter front-end deadtime. The preamplifier stage also offers the possibility of using other types of photomultiplier devices such as SiPM. The ASIC architecture…
Light-by-light polarization control for telecommunication applications
2010
In this work, we report for the first time the experimental achievement of an all-fibered polarization attraction, which can occur in optical fibers at telecommunication wavelengths. More precisely, we have experimentally shown that is possible to all-optically control and stabilize the state of polarization of a 10 Gbit/s telecommunication signal through the injection of a counter-propagating control pump wave. Eye diagrams recordings and bit error rate measurements have shown that this new type of all-optical function, almost lossless and instantaneous has a promising potential for telecommunication applications.
Propagation, Stability and Interactions of Novel Three-Wave Parametric Solitons
2006
International audience; We found a new class of analytic soliton solutions that describe the parametric wave mixing of optical pulses in quadratic nonlinear crystals. We analyze the stability properties, interactions and collisions of these solitons.
Up to Date Version of a Computer-Driven Noise Figure Measuring System for the Simultaneous Determination of Noise, Gain and Scattering Parameters of …
1995
The complete characterization of microwave transistors in terms of (four) noise, (four) gain and scattering parameters sets ({N), {G) and [SI, respectively) vs. frequency and bias conditions (and also vs. decreasing temperature, if required) is the first and most important step to design low noise amplifiers (LNAs). The characterization of the device under test (DUT) in terms of [SI is friendly by means of commercial Automatic Network Analyzer; then the { G) set may be determined by computation.
Analytical Dynamics of Optical Similaritons
2007
We analytically describe the attraction of parabolic pulses towards a self-similar state in weakly dispersive nonlinear fibers with linear gain.