Development of Waveguide Semiconductor Switches of Microwave Radiation in the 70- and 260-ghz Ranges

Abstract

UDC 537.52We have developed, manufactured, and studied experimentally prototypes of microwave switches operated in the 70-and 260-GHz frequency ranges and controlled by pulses of optical laser radiation. The results of their numerical simulation by the finite-difference time-domain (FDTD) method are presented, along with the design parameters of the prototypes. The switch speed is equal to 1 ns, and the microwave tuning frequency range amounts to about 10%. The process of switching with the use of a low-cost semiconductor optical laser (with a wavelength of 532 nm and a continuous-wave power of 200 MW) is demonstrated experimentally at a switched-radiation frequency of 266.68 GHz.

Long-Pulsed Modulation Regimes of Subterahertz Nanosecond Waveguide Switches

“…Sub-terahertz resonator cavity-based switches [1,2] with an active semiconductor element of Gallium Arsenide (GaAs) driven by laser pulses are used to cut microwave signal from a generator to series of wave packets. Intrinsic properties of Gallium Arsenide crystal help to achieve nanosecond level of switching performance with green driving laser emission [3].…”

Laser-driven semiconductor switch for generating nanosecond pulses from a megawatt gyrotron

“…Laser-driven semiconductor switches (LDSSs) are of great use in producing short RF pulses in the microwave to far-infrared range. [1][2][3][4][5] An LDSS-based system, like the experiment presented in this paper, operates by using a laser to induce temporary reflectance in a semiconductor wafer. The wafer subsequently reflects RF from a source for a short time period ranging from picoseconds to seconds.…”

“…1 The fundamental behavior of LDSS systems in generating short pulses has been well characterized by previous experiments at lower RF power levels. 3,4,[6][7][8][9][10][11] Theoretical work investigating the semiconductor response has been completed for both fundamental waveguide and free-space systems. 3,12,13 LDSS systems have been applied to electron spin resonance spectroscopy, notably in 2014 using a 150 W gyrotron at 154 GHz as the RF source.…”

“…The recombination time of the GaAs wafer is approximately 30 ns and is comparable to values seen in previous experiments that used a laser pulse of a similar duration. 3,4 The reflected power from the Si wafer begins to decay almost immediately after the laser pulse reaches its peak intensity, resulting in a fall time on the order of 10 ns for the Si reflected pulses. This is much shorter than was found in most previous experiments, which observed recombination times that range from hundreds of nanoseconds to milliseconds in undoped high-resistivity Si wafers.…”

260 GHz CW gyrotron heating substitution with second-long laser pulses in waveguide semiconductor switches

“…Sub-Terahertz waveguide semiconductor switches driven by laser emission [1] are used to cut a continuousworking (CW) microwave emission to series of wave packets [2,3]. The main advantage of the switches is low distortion to the phases of the packets' high frequency fillings at the output [4].…”