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We report the experimental demonstration of a gyrotron traveling-wave-tube amplifier at 250 GHz that uses a photonic band gap (PBG) interaction circuit. The gyrotron amplifier achieved a peak small signal gain of 38 dB and 45 W output power at 247.7 GHz with an instantaneous -3  dB bandwidth of 0.4 GHz. The amplifier can be tuned for operation from 245-256 GHz. The widest instantaneous -3  dB b...

We present measurements of the power noise that is due to optical amplification in a laser-diode-pumped Nd:YAG free-space traveling-wave linear amplifier in a master-oscillator-power-amplifier configuration. The quantum noise behavior of the optical amplifier was demonstrated by use of InGaAs photodetectors in a balanced detection configuration, at a total photocurrent of 100 mA and in a freque...

We extend the theory for a Josephson junction travelling wave parametric amplifier (TWPA) operating in three-wave mixing regime and we propose scheme achieving high gain. The continuous three-mode model [P. K. Tien, J. Appl. Phys. 29, 1347 (1958)] is on one hand extended to describe discrete chain of junctions at frequencies close spectral cutoff where there no up-conversion. On other hand, als...

Results of design and simulation of a 0.2 THz traveling-wave-tube vacuum power amplifier with a sheet electron beam and grating slow-wave structure (SWS) are presented. Electromagnetic properties of the SWS such as dispersion and interaction impedance are calculated. Smallsignal and large signal gain curves are studied.

Previously reported quasi-optical amplifier arrays have limited bandwidth and suffer from poor input/output isolation. These prsbllems can be solved by using traveling wave antennas and distributed amplifier techniques. FII'TD simulations of a linearly tapered slot array topology demonstrate very broadband quasioptical transitions are feasible with small unitcell aperture. Experiments using a s...

We develop a wideband traveling-wave formalism for analyzing quantum mechanically a degenerate parametric amplifier. The formalism is based on spatial differential equations-spatial Langevin equations-that propagate temporal Fourier components of the field operators through the nonlinear medium. In addition to the parametric nonlinearity, the Langevin equations include absorption and associated...