40-GHz-Bandwidth Heterodyne Detection of Terahertz-Waves by Waveguide-Input Fermi-Level Managed Barrier Diode Module

A J-band waveguide-input Fermi-level managed barrier diode module was developed for broadband heterodyne detection of THz-waves. In the direct (square-law) detection mode, the fabricated module showed a 3-dB bandwidth that covers the entire J-band. In the heterodyne detection mode, it exhibited an intermediate frequency (IF) bandwidth of about 40 GHz and linear dependence of IF output power against input signal power. The minimum noise-equivalent power obtained was as low as 7 × 10
^-18
W/Hz at around 300 GHz for a very low local oscillator power of 30 μW.