Multi‐Octave All‐Dielectric Directional Coupler Using Integrated Half‐Mirror for Ultrawideband Terahertz Systems

Abstract

Network analysis is foundational to calibrated instrumentation for practical handheld devices, and the directional coupler is the fundamental passive component that makes it possible. In this work, a terahertz‐range handheld integrated‐photonic directional coupler is reported with broad operation bandwidth spanning more than two octaves. The design adapts the underlying ray‐tracing principles of classical parabolic reflectors and optical beam splitters to a monolithic substrateless micro‐machined silicon structure. This advance holds the potential to unlock a new generation of terahertz systems, including vector network analyzers, that combine the broad bandwidth of bulky quasi‐optical terahertz systems with the handheld form‐factor and convenient, repeatable port access of guided‐wave approaches.