We report experimental results demonstrating 54% power conversion efficiency ~43% energy conversion efficiency!, from a two-stage X-band traveling wave tube amplifier designed for high-power operation. The first stage of the amplifier is a 12-cm-long Boron Nitride dielectric section used to modulate the electron beam. The second stage consists of a long high-phase-velocity bunching section foll...

The analysis of a Ka-band gyrotron Travelling Wave Tube (gyro-TWT) amplifier using a uniform cylindrical waveguide as its interaction circuit has been presented for the TE01 mode of operation a self-consistent nonlinear analysis in the large signal regime. The analysis predicts that the saturated peak output power of ~ 134 kW with a power conversion efficiency of ~ 22.7 %. The saturated gain ha...

We report on the implementation of a near-quantum-limited, traveling-wave parametric amplifier that uses three-wave mixing (3WM). To favor amplification by 3WM, we use superconducting nonlinear asymmetric inductive element (SNAIL) loops, biased with dc magnetic flux. In addition, equip device dispersion engineering features to create stopband at second harmonic pump and suppress propagation hig...

In this paper, Exp-function and (G′/G)expansion methods are presented to derive traveling wave solutions for a class of nonlinear space-time fractional differential equations. As a results, some new exact traveling wave solutions are obtained.

We develop the concept of quasi-phasematching (QPM) by implementing it in recently proposed Josephson traveling-wave parametric amplifier (JTWPA) with three-wave mixing (3WM). The is based on a ladder transmission line consisting flux-biased radio frequency superconducting quantum interference devices (SQUIDs) whose nonlinearity χ ( 2 )-type. QPM achieved 3WM process, ω p = s + i (where ωp, ωs,...

A theory of four-wave mixing in semiconductor laser media is developed by considering the contributions of both the gain and index gratings created by the carrier-density modulation occurring at the beat frequency of the pump and the probe waves. The general formalism can be applied to semiconductor lasers operating below or above threshold. As an illustration, we consider the case in which the...

The advent of ultra-low noise microwave amplifiers revolutionized several research fields demanding quantum-limited technologies. Exploiting a theoretical bimodal description linear phase-preserving amplifier, in this contribution we analyze some the intrinsic properties model architecture (i.e., an rf-SQUID based Josephson Traveling Wave Parametric Amplifier) terms amplification and generation...

Results are presented on the development of a two stage high-efficiency, high-power 8.76-GHz traveling-wave tube amplifier. The work presented augments previously reported data on a single stage amplifier and presents new data on the operational characteristics of two identical amplifiers operated in series and separated from each other by a sever. Peak powers of 410 MW have been obtained over ...