We have obtained parametric gain at 19 GHz from a distributed Josephson junction parametric amplifier whose active gain medium consists of a series array of 1000 Josephson junctions embedded in a coplanar waveguide. When cooled to 1.7 K the amplifier provides 16 dB gain in a mode where the internally generated double sideband noise referred to input is 0.560.1 K. This noise is consistent with N...

A selective and sensitive quartz enhanced photoacoustic spectroscopy (QEPAS) sensor, employing an erbium-doped fiber amplifier (EDFA), and a distributed feedback (DFB) laser operating at 1582 nm was demonstrated for simultaneous detection of ammonia (NH₃) and hydrogen sulfide (H₂S). Two interference-free absorption lines located at 6322.45 cm(-1) and 6328.88 cm(-1) for NH₃ and H₂S detection, re...

For many years Distributed Denial-of-Service attacks have been known to be a threat to Internet services. Recently a configuration flaw in NTP daemons led to attacks with traffic rates of several hundred Gbit/s. For those attacks a third party, the amplifier, is used to significantly increase the volume of traffic reflected to the victim. Recent research revealed more UDP-based protocols that a...

Stable picosecond soliton transmission is demonstrated numerically by use of concatenated gain-distributed nonlinear amplifying fiber loop mirrors (NALMs). We show that, as compared with previous soliton transmission schemes that use conventional NALMs or nonlinear optical loop mirror and amplifier combinations, the present scheme permits a significant increase of loop-mirror (amplifier) spacin...

Pulse propagation in high-gain optical fiber amplifiers with normal group-velocity dispersion has been studied by self-similarity analysis of the nonlinear Schrödinger equation with gain. For an amplifier with a constant distributed gain, an exact asymptotic solution has been found that corresponds to a linearly chirped parabolic pulse that propagates self-similarly in the amplifier, subject to...

This paper describes a new approach for designing analog cubic predistorters in view of minimizing non linear distortion introduced by the high power amplifier (I-IPA) in microwave radio links. The approach is based on a global mean squared error minimization between the input to the predistorter and the output of the power amplifier, rather than on the elimination of the cubic term. In this ma...

Abstract This paper proposes the use of an inverse class-E amplifier with a tunable parallel resonator at the output port in order to obtain a high power-added efficiency (PAE) and output power in a wide frequency range. The tunable resonator circuit has a constant Q factor in the operating frequency range, and since the circuit has a varactor diode, the inductor and capacitor values of the res...

Recently, Low noise amplifier versatile used in modern wireless communication like Wi-Max, WLAN, GSM, Bluetooth and satellite communication. Low Noise amplifier have important feature like amplify the signal with rejection of noise. Low noise amplifier in modern communication used as filter with amplifier. In recent scenario low noise amplifier available in wide band, single band, multi-band fr...

The passive sections of a monolithic device must have a wider bandgap than the active regions to reduce losses due to direct interband absorption. Such bandgap engineering is usually realized by complicated regrown butt-joint or selective-area growth techniques. We, however, have developed a simple, flexible and low-cost alternative technique – quantum well intermixing (QWI) – to increase the b...