High-performance terahertz optoelectronic receivers enabled by monolithic integration of SBDs and UTC-PDs: modelling and design

In this work, we propose the monolithic integration of Schottky barrier diodes (SBDs) and uni-traveling-carrier photodiodes (UTC-PDs) to implement optoelectronic terahertz heterodyne receivers. By performing efficient frequency-mixing with SBDs and generating the local oscillator (LO) signal by optical means in UTC-PDs the virtues of both electronic and photonic domains are incorporated into the same receiver. A complete modelling process including semiconductor, electromagnetic, and non-linear harmonic domains is used to design a subharmonic mixer (SHM) at 220-330 GHz using antiparallel SBDs within the UTC-PD epitaxial structure. This is done in co-planar waveguide (CPW) on a silicon oxynitride film and semi-insulating indium phosphide substrate. Simulations show remarkable performance featuring a dual-side-band (DSB) conversion loss as low as 8.2 dB, a noise temperature of 2500 K, and an intermediate-frequency (IF) 3dB-bandwidth of 25 GHz, which is achieved with a driving photocurrent of 5-15 mA.