Terahertz coherent receiver using a single resonant tunnelling diode

Abstract

Towards exploring advanced applications of terahertz (THz) electromagnetic waves, great efforts are being applied to develop a compact and sensitive THz receiver. Here, we propose a simple coherent detection system using a single resonant tunnelling diode (RTD) oscillator through self-oscillating mixing with an RTD oscillator injection-locked by a carrier wave. Coherent detection is successfully demonstrated with an enhancement in the sensitivity of >20 dB compared to that of direct detection. As a proof of concept, we performed THz wireless communications using an RTD coherent receiver and transmitter. We achieved 30-Gbit/s real-time error-free transmission, which is the highest among all electronic systems without error correction to date. Our results show that the proposed system can reduce the size and power consumption of various THz systems including sensing, imaging and ranging, which would enable progress to be made in a wide range of fields in such as material science, medicine, chemistry, biology, physics, astronomy, security, robotics and motor vehicle.

Terahertz Emitter Using Resonant-Tunneling Diode and Applications

“…Basic research into various applications of RTD oscillators has begun, including for imaging [ 36 ], sensors [ 37 ], linear encoders [ 38 ], communication [ 39 , 40 , 41 , 42 , 50 ], and radars [ 43 , 44 , 45 , 46 ], in addition to spectroscopy [ 47 ] shown in the previous section. It is a future task to develop various applications of RTD oscillators.…”

“…Wireless transmission using RTDs as detectors has also been reported [ 49 , 50 ]. The RTD is expected to have a high sensitivity in THz detection, due to the strong non-linearity in the I–V curve, which is the same principle as the detection in SBD (although bias voltage must be applied to use the strong non-linearity in RTD).…”

“…The RTD is expected to have a high sensitivity in THz detection, due to the strong non-linearity in the I–V curve, which is the same principle as the detection in SBD (although bias voltage must be applied to use the strong non-linearity in RTD). Other than the detection using such non-linearity, a self-homodyne THz detection mode has recently been reported [ 50 , 51 ]. In this mode, the THz signal is detected by an RTD oscillator which is oscillating near the frequency of the irradiated signal.…”

“…In this paper, we review recent developments and applications of THz sources using RTD oscillators. Although RTDs can also be used as THz detectors [ 48 , 49 , 50 , 51 ], here, we only describe RTD THz sources, except for a brief introduction of the application of RTD THz detectors for wireless communications.…”

Optical heterodyne AND operation as emulation of physical layer security at wireless communication

“…The configuration reduces a possibility for third parties of detecting the real data from each wireless signal. This system is enabled by THz coherent detection technologies [22,23,24,25] and our novel high-frequency wave beam steering via an UTC-PD/antenna array [19,20,21]. In this letter, as an emulation of the proposed wireless heterodyne AND operation system, we construct an optical heterodyne AND operation system and experimentally demonstrate the feasibility of the secured communication mechanism.…”