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In this paper, we have demonstrated a 5G/terahertz integrated wireless network, significantly shrinking down the construction and maintenance cost; this integrated system prototype has shown several desirable advantages - low cost, easy to operate, and ultra-broadband frequency tunability.

In this paper, we designed and simulated a polarization-insensitive InGaAs-based Continues wave THz emitter. In the proposed structure, the metallic meshes geometry is designed to increase optical transmission to the active area near the contact electrodes. The nanometer structured metallic features also enhance the local bias field near contact edges where the most photoexcited carriers are generated, leading to enhanced THz current. The simulation results demonstrate that the optimized structure generates 51 μw THz power under unpolarized 200 mW optical pump power at 500 GHz beat frequency.

In this Letter, we propose and experimentally validate a sparse deep learning method (SDLM) for terahertz indoor wireless-over-fiber by transmitting a 16-quadrature amplitude modulation (QAM) orthogonal frequency-division multiplexing (OFDM) signal over a 15-km single-mode fiber (SMF) and a wireless link distance of 60 cm at 135 GHz through a cost-effective intensity-modulated direct detection (IM-DD) communications system. The proposed SDLM imposes the L1-regularized mechanism on the cost function, which not only improves performance but also reduces complexity when compared with traditional Volterra nonlinear equalizer (VNLE), sparse VNLE, and conventional DLM. Our experimental findings show that the proposed SDLM provides viable options for successfully mitigating nonlinear distortions and outperforms conventional VNLE, conventional DLM, and SVNLE with a 76%, 72%, and 61% complexity reduction, respectively, for 8-QAM without losing signal integrity.

A piezotronic pulsed GaN-based photoconductive TeraHertz (THz) emitter is proposed and simulated for the first time. In this paper, we benefit from high break down-voltage, thermal conductivity, and saturation velocity of GaN, to design a pulsed antenna-less THz emitter. The proposed emitter consists of asymmetric metal-semiconductor-metal structure. Moreover, strong coupling of semiconducting/piezoelectric properties in GaN, allows modulation of the dissimilar Schottky barriers, leading to tunable THz output power and bandwidth. Our simulation results demonstrate that applying an external strain of about 4% results in 26% enhancement in the radiated THz power, while output bandwidth is improved about 4.2%. The proposed structure is promising for emerging reconfigurable THz emitters, capable of being tunable by external strain as a controlling gate.

Recently Controlling the electromagnetic wave, especially in terahertz range is highly demanded due to the development of practical devices and application systems. In this paper, we propose a scheme to design tunable abnormal reflection structure consisting of molybdenum disulfide (MoS 2 ) array on a grounded SiO 2 and a gold layer beneath them to reflect the terahertz wave. In this structure, MoS 2 can be controlled by intrinsic carrier density or voltage bias, to control the electromagnetic reflected beam at terahertz frequency. By adjusting the geometric dimensions of the MoS 2 elements, the reflection phase can cover the range of 0–2π with linear phase shift, thus abrupt phase shifts can be introduced to design the reflected wavefront. Furthermore, the reflective phase gradient over the structure can be switched by controlling the intrinsic carrier density or voltage bias of the MoS 2 , hence reflected beam directions can be switched dynamically. The proposed scheme will bring much freedom in the design of beam manipulation devices and may be applied to terahertz radiation control. Numerical simulations verify the Snell’s law generalized at working frequency and far field scattering illustrate the abnormal reflection.

An array of unbiased pulsed GaN-based terahertz emitters based on excitation of different waveguide modes in the metallic contact grating is proposed and simulated for the first time. The proposed emitter consists asymmetric metal semiconductor-metal, so dissimilar Schottky contacts induce internal electric field that accelerates the photogenerated carriers. Furthermore, by taking advantage of plasmonic cavity modes for specific dimensions of the emitter array, it is shown that THz photocurrent can be enhanced about 5 times in comparison with the unbiased emitter array of the same area. We demonstrate that, for appropriate dimensions of the top metal contact in such a THz emitter array, the first order guided modes of the sub-wavelength nano-slit waveguides will be formed between two adjusted metal contacts, which leading to an enhanced optical absorption and the consequent THz photocurrent in the active region. Finally, we have designed a THz antenna with maximum gain of 6.5, and bandwidth of 400 GHz, which is coupled to the proposed THz emitter array to improve the output radiation power.