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In this paper experimental measurement of a W-band gyrotron travelling wave amplifier (gyro-TWA) which is upgraded to operate at a high output power and wide frequency band will be presented. The gyro-TWA based on helically corrugated interaction region and cusp electron beam source can output a maximum power of ∼5 kW at its centre frequency of ∼94 GHz with an instantaneous frequency bandwidth of...
A low-frequency electrical spectrum analysis method is researched for evaluating broadband characteristics of high-speed dual-parallel Mach-Zehnder modulators (DPMZMs) based on dual-frequency modulation and fixed-frequency bias. The method enables the broadband and high-resolution evaluation for the modulation depth and half-wave voltage of a high-speed DPMZM by using a low-frequency photodetector...
The design and experiment of an upgraded W-band gyrotron travelling wave amplifier (gyro-TWA) based on a helically corrugated interaction region is presented. The upgrade of the input coupler, output window, corrugated output mode converter enabled a measured output power of a few kWs from the gyro-TWA with an unsaturated gain of up to 40 dB and a 3 dB frequency bandwidth of at least 5.5 GHz.
Latest development and experimental study of a W-band gyro-TWA with a helically corrugated waveguide and a cusp electron gun are presented. With an input seed signal from an 1.5 W, 90–96 GHz solid state source a gain of 27 dB was measured from the experiment. The bandwidth of the gyro-TWA was measured to be at least 5 GHz.
A five-channel frequency-division multiplexing (FDM) fiber laser sensor array based on multilongitudinal mode fiber lasers (MLMFLs) and beat frequency demodulation was proposed. Detailed theoretical analysis of the FDM principle was also described. The potential application of the MLMFL-based FDM for strain measurement was further experimentally studied. The strain sensitivity of $-$0.92 kHz/ $\mu\varepsilon$...
Latest experimental developments of W-band gyro-devices with helically corrugated waveguides and a cusp electron gun are presented. The cusp generated a 40 keV, 1.5 A axis-encircling electron beam. Helical corrugated waveguides have ideal dispersive properties which improve the frequency tuning range of a gyrotron backward wave oscillator (gyro-BWO) whilst maintaining the already good efficiency of...
This paper presents a highly efficient GaN Doherty power amplifier (DPA) with 100 MHz signal bandwidth and 40 dBm average output power for 3.5 GHz LTE-Advanced application. The carrier and peaking amplifiers are fabricated using 60-W GaN HEMT and implemented with unequal saturation power (Psat) in order to maintain high efficiency at large backed-off power (BOP). The highest drain efficiency (DE)...
We experimentally demonstrate a PMD monitoring technique utilizing the polarizer and low-speed detector for 80-Gb/s pol-muxed RZ-DPSK. RF power increment of 16.2 dB, insensitive to 0~100 ps/nm chromatic dispersion, is measured in the presence of 0~12 ps DGD.
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