Yang Chengyue

A 330–500 GHz Zero-Biased Broadband Tripler Based on Terahertz Monolithic Integrated Circuits

A 330–500 GHz zero-biased broadband monolithic integrated tripler is reported. The measured results show that the maximum efficiency and the maximum output power are 2% and 194 μW at 348 GHz. The saturation characteristic test shows that the output 1 dB compression point is about −8.5 dBm at 334 GHz and the maximum efficiency is obtained at the point, which is slightly below the 1 dB compression point. Compared with the conventional hybrid integrated circuit, a major advantage of the monolithic integrated circuit is the significant improvement of reliability and consistency. In this work, a terahertz monolithic frequency multiplier at this band is designed and fabricated.

Planar InP-based Schottky barrier diodes for terahertz applications

Based on characteristics such as low barrier and high electron mobility of lattice matched In0.53Ga0.47As layer, InP-based Schottky barrier diodes (SBDs) exhibit the superiorities in achieving a lower turn-on voltage and series resistance in comparison with GaAs ones. Planar InP-based SBDs have been developed in this paper. Measurements show that a low forward turn-on voltage of less than 0.2 V and a cutoff frequency of up to 3.4 THz have been achieved. The key factors of the diode such as series resistance and the zero-biased junction capacitance are measured to be 3.32 Ω; and 9.1 fF, respectively. They are highly consistent with the calculated values. The performances of the InP-based SBDs in this work, such as low noise and low loss, are promising for applications in the terahertz mixer, multiplier and detector circuits.

Compact 2×2 Multi-Mode Interference Couplers with Uneven Splitting-Ratios Based on Silicon Nanowires

Two types of uneven splitting-ratio 2×2 multi-mode interference (MMI) couplers based on silicon nanowires are designed, fabricated and characterized. The splitting ratios are 85:15 and 72:28, respectively. The devices have compact sizes and low excess losses. The footprints of the rectangular MMI region are only about 3μm×18μm and 3μm×14μm, and the minimum excess losses (ELs) are 1.30 dB and 0.82 dB. The measured splitting-ratios are consistent with the designed values. Based on their performance, these 2×2 MMI couplers are suitable candidates for the coupling section of microring resonators where a large resonance bandwidth is required for high speed signal processing. The uneven splitting capability also provides a convenient way to further optimize the Q factor and the bandwidth of the resonator.