Switchable Polarization Beam Splitter Based on GST-on-Silicon Waveguides

Abstract

A switchable polarization beam splitter utilizing GST-on-silicon waveguides is introduced and comprehensively investigated in this paper. Based on the phase matching and mode hybridization, structural parameters of the presented device are optimized by using the particle swarm optimization algorithm and finite difference time domain method, so that the output fundamental transverse-electric (TE 0) and transverse-magnetic (TM 0) modes can be switched by controlling the phase state of GST and the device exhibits broad bandwidth, low crosstalk, and high polarization extinction ratio. For the designed device with the amorphous GST, the crosstalk is lower than −23.40 dB and the polarization extinction ratio is larger than 21.35 dB over the C-band. In the case of the crystalline GST, within the C-band, the crosstalk of less than −27.37 dB and the polarization extinction ratio of greater than 21.37 dB are achieved.

Heterostructures made from bone-like plasmonic Au nanoantennas and ZnO quantum dots for broadband photodetectors

“…All the BLAuNAs/ZnO heterostructures photodetectors delivered a low dark current ( I d ) because the high crystallinity of ZnO QDs largely reduces the carrier concentration generated from the defects and impurities. 47 However, their I d is higher than that of the pure ZnO QDs photodetector because the incorporation of the conductive BLAuNAs greatly facilitates the transport of charge carriers generated between the two collection electrodes. The photocurrent ( I ph ) of each photodetector gradually increases with the increase of the bias voltage.…”