Demonstration of 144-Gbps Photonics-Assisted THz Wireless Transmission at 500 GHz Enabled by Joint DBN Equalizer

Abstract

The THz wireless transmission system based on photonics has been a promising candidate for further 6G communication, which can provide hundreds of Gbps or even Tbps data capacity. In this paper, 144-Gbps dual polarization quadrature-phase-shift-keying (DP-QPSK) signal generation and transmission over a 20-km SSMF and 3-m wireless 2 × 2 multiple-input multiple-output (MIMO) link at 500 GHz have been demonstrated. To further compensate for the linear and nonlinear distortions during the fiber–wireless transmission, a novel joint Deep Belief Network (J-DBN) equalizer is proposed. Our proposed J-DBN-based schemes are mainly optimized based upon the constant modulus algorithm (CMA) and direct-detection least mean square (DD-LMS) equalization. The results indicate that the J-DBN equalizer has better bit error rate (BER) performance in receiver sensitivity. In addition, the computational complexity of the J-DBN-based equalizer can be approximately 46% lower than that of conventional equalizers with similar performance. To our knowledge, this is the first time that a novel joint DBN equalizer has been proposed based on classical algorithms. It is a promising scheme to meet the demands of future fiber–wireless integration communication for low power consumption, low cost, and high capacity.

Phase Stabilization of a Terahertz Wave Using Mach–Zehnder Interference Detection

“…According to the graph, frequencies above 300 GHz are mostly handled utilizing opto-electronic techniques. The greatest transmission bit rate of 110 Gbit/s has been reached among all-electronics approaches at 240 GHz [35], while the opto-electronics approach has hit 140 Gbit/s at 500 GHz [36].…”

Editorial for the Special Issue on Broadband Terahertz Devices and Communication Technologies

“…With the advances in broadband terahertz devices and the design of novel digital signal-processing routines, high-speed terahertz communications could be realized. In this Special Issue, three terahertz communicating systems were analyzed and demonstrated [ 9 , 10 , 11 ], including a 144 Gbps photonics terahertz communication system working at 500 GHz [ 9 ], a W-band communication and sensing convergence system [ 10 ], and an analysis of secure terahertz communications with perfect electric conductor (PEC) and multiple eavesdroppers [ 11 ].…”

“…Terahertz wireless communication systems based on photonics have emerged as promising candidates for 6G communications, capable of providing hundreds of Gbps or even Tbps data capacity. Liu et al [ 9 ] experimentally demonstrated a 144 Gbps dual-polarization quadrature-phase-shift-keying (DP-QPSK) signal generation and transmission over a 20 km SSMF and 3 m wireless 2 × 2 MIMO link. A novel and low-complexity joint deep belief network (J-DBN) equalizer was proposed to compensate for linear and nonlinear distortions during fiber–wireless transmission.…”