High-Performance and Low-Crosstalk Terahertz Plasmonic Crossings

For terahertz integrated systems, an intersection between waveguides is inevitable and is often accompanied by considerable crosstalk and loss. Here, we propose and experimentally demonstrate a novel type of crossing with a footprint less than 0.2×0.2 mm
²
for terahertz surface plasmon polariton waveguiding. The crossing loss is estimated by investigating a sequence of waveguides with one, two and three crossings. By optimizing the crossover structure to suppress crosstalk, the measured loss is as low as -3.86 dB and the crosstalk is less than -19.06 dB/crossing at 0.55 THz. The proposed crossing structure is compact and has low loss and crosstalk within a broad band, which will pave the way for a wide range of new applications for THz integrated systems.