Terahertz Absorptive Amplitude Modulation Enabled by Dual-Path Coherent Interference

Current terahertz direct modulators suffer from significant reflections during modulation. This paper proposes an absorptive terahertz amplitude modulator based on dual-path coherent interference by integrating a ring circuit structure with Schottky diodes. Through dynamic regulation of interference effects between dual paths by controlling diode states, coherent modulation at the output port is achieved while effectively suppressing reflections under modulated conditions. The designed 220 GHz central frequency modulator demonstrates return loss below 16 dB in both “ON/OFF” states, successfully overcoming the high-reflection issue inherent to traditional impedance-mismatch-based modulators. This approach breaks through the reflection bottleneck of conventional impedance modulation methods and provides a novel pathway for high-performance terahertz communication devices.