Low Loss Suspended Silicon Waveguide And Photonic Crystal For Thz Regime

Terahertz integrated photonic circuits are used in many applications. In recent years we are witnessing an unprecedented development of applications of THz waves such as identifications of pollutants, safety imaging, high data transmission, detection of organic molecules in space... The majority of these systems however still rely on voluminous, free-space implementations necessitating powerful bulky THz sources and detectors. The development of a low-loss chip-scale integrated photonic platform for THz waves and the associated increased energy confinement could bring about a performance/cost ratio for these technologies. Up till now reports of integrated mm-wave and THz integrated circuits have been few and far between, hindered by important on-chip waveguide losses, and requiring important technological fabrication efforts [1], [2]. In this work we present experimental work on a low-loss and low-cost, suspended silicon waveguide technology at millimetric scale for THz frequencies. Specifically, we present loss extractions measured on waveguides of varying length and first results on integrated cavities, obtained by etching a 1D crystal in the suspended waveguide. These results prove versatility and viability of this new technological platform for integrated THz sensing and spectroscopy applications.