THz analog to digital converter using single sided spoof surface plasmon polariton waveguide

In this paper, an analogue-to-digital convertor (ADC) utilizing the single sided spoof surface plasmon polariton (SS-SSPP) waveguide is presented. The proposed ADC device consists of three stages: first stage is the Mach-Zehnder interferometer (MZI) with two arms which acts as a beam steering device, second is free space propagation stage, and third is the detector arrays to convert analog signal into digital input. The SSPP waveguide includes periodic grooves, which are filled with a thin layer of doped semiconductor. In order to alter the refractive index of the semiconductor the depletion mode has been used. It is demonstrated that the ADC can operate with sampling speed around 47 GS/s.