ErAs:In(Al)GaAs Terahertz Transceivers for Compact Pulsed Free Space Photonic Vector Network Analyzer

We present ErAs:In(Al)GaAs-based terahertz transceiver modules, comprising transmitter and receiver components integrated on a single chip. The transceiver module is employed in a two-port single-path (TxRx-Rx) or 1.5-port pulsed free space photonic vector network analyzer setup, wherein the second receiver is an individual ErAs:InGaAs photoconductor. This configuration allows for simultaneous extraction of transmission and reflection coefficients or scattering parameters S₂₁ and S₁₁. The system achieves a peak dynamic range of ∼59 dB for S₂₁ and ∼43 dB for S₁₁ at a bandwidth reaching ∼3.5 THz for the transmission and ∼2.5 THz for the reflection path. These values are obtained by averaging over 500 traces at a scan rate of 4 Hz. The system exhibits superior frequency coverage compared to commercially available electronic vector network analyzers, thus offering a compact, cost-effective, broadband characterization solution for the benchmarking of terahertz devices and components.