Low-loss terahertz waveguide Bragg grating using a two-wire waveguide and a paper grating.

We propose a low-loss terahertz waveguide Bragg grating (TWBG) fabricated using a plasmonic two-wire waveguide and a micromachined paper grating for potential applications in terahertz (THz) communications. Two TWBGs were fabricated with different periods and lengths. Transmission spectra of these TWBGs show 16 dB loss and 14 dB loss in the middle of their respective stop bands at 0.637 and 0.369 THz, with Q factors of 142 and 105, respectively. Insertion loss of 1-4 dB in the whole 0.1-0.7 THz region was also measured. Finally, TWBG modal dispersion relations, modal loss, and field distributions were studied numerically, and low-loss, high-coupling-efficiency operation of TWBGs was confirmed.