Ultra-Low-Loss and Broadband All-Silicon Dielectric Waveguides for WR-1 Band (0.75–1.1 THz) Modules

Abstract

This study presents ultra-low-loss and broadband all-silicon dielectric waveguides for the WR-1 band (0.75–1.1 THz). The waveguides are built in high-resistivity silicon (10 kΩ-cm) and integrated with supportive frames fabricated from the same silicon wafer in a single etch process to achieve a compact design. We pursued low-loss, broadband, substrateless, unclad and effective medium waveguides. Smaller propagation losses of 0.3 dB/cm and 0.1 dB/cm were achieved for the unclad and effective medium waveguides, respectively. The 3 dB bandwidth was not encountered in the frequency range of interest and was as broad as 350 GHz. An unclad waveguide was employed to devise a Y-junction to demonstrate its practical applications in terahertz imaging. An integrated circuit card was successfully scanned. In addition, we developed unclad waveguide, effective medium waveguide, and Y-junction modules. The modules incorporated an input/output interface compatible with a standard WR-1 flange (254 μm × 127 μm). Unlike the conventional hollow waveguide modules, the unclad waveguide and effective medium waveguide modules reported total loss improvements of 6 dB and 8 dB, respectively, across the operation band. Our results provided a systematic way of achieving low-loss, compact, and versatile modules in the WR-1 band based on all-dielectric-waveguide platforms.

Phase-Controllable Spoof Surface Plasmon Coupling From Bull's Eye Aperture to Planar Silicon Waveguide in the Terahertz Band

“…The two branched ends are defined as Port 3 and Port 4, and the end before branching is defined as Port 5. It is worth mentioning that the Y-branched waveguide itself has already been reported for splitters and combiners in the terahertz region, as well as for near-field probing applications [45,46].…”

Photonic Radar for 3D Imaging: From Millimeter to Terahertz Waves

“…The THz band silicon waveguide platform is one candidate for integrating passive devices above the sub-THz band due to its superior low loss of <0.1 dB/cm [80], [81]. Integrated couplers at 0.6 and 1 THz have been installed for THz band imaging applications [4], [16].…”

“…Furthermore, radar signals up to ∼1 THz with more than 100 GHz bandwidth can be generated and detected using highend electronic instruments, such as vector network analyzers (VNAs), based on which a series of 3D imaging demonstrations have been reported ranging from the MMW band to the THz band [13], [14], [15], [16]. These refined techniques offer superior bandwidth and mW-order output power.…”

Terahertz link with orthogonal polarization over silicon dielectric waveguide

“…In the meantime, advances in photonics‐inspired devices have enabled the development of several dielectric THz waveguides made of silicon (Si) as a dielectric material using high‐resistivity Si, such as photonic crystal, effective medium (EM), and wire unclad waveguides. Si waveguides have reported low losses of < 0.1 dB/cm for photonic crystal at 0.3 THz [3], EM cladding and unclad waveguides at 0.9 THz [12], respectively. Such a low loss can be attributed to the reduction of the absorption loss of high‐resistivity Si in the THz region [12].…”

“…Si waveguides have reported low losses of < 0.1 dB/cm for photonic crystal at 0.3 THz [3], EM cladding and unclad waveguides at 0.9 THz [12], respectively. Such a low loss can be attributed to the reduction of the absorption loss of high‐resistivity Si in the THz region [12]. Indeed, with increase in frequency, the absorption loss due to free carriers in Si decreases [13].…”