Tunable topological charge vortex microlaser

The orbital angular momentum (OAM) intrinsically carried by vortex light beams holds a promise for multidimensional high-capacity data multiplexing, meeting the ever-increasing demands for information. Development of a dynamically tunable OAM light source is a critical step in the realization of OAM modulation and multiplexing. By harnessing the properties of total momentum conservation, spin-orbit interaction, and optical non-Hermitian symmetry breaking, we demonstrate an OAM-tunable vortex microlaser, providing chiral light states of variable topological charges at a single telecommunication wavelength. The scheme of the non–Hermitian-controlled chiral light emission at room temperature can be further scaled up for simultaneous multivortex emissions in a flexible manner. Our work provides a route for the development of the next generation of multidimensional OAM-spin-wavelength division multiplexing technology.

Research on Temporal Cloaked Signal Transmission Based on Time Reversal Technique

Based on the theory of time reversal technique and through the use of temporal dispersive delay lines, this paper presents a demonstration of temporal cloaked signal transmission at microwave frequencies. When compared with a conventional signal processing system, the related dispersive delay lines are not required to provide linear group delay response. Thus the proposal simplifies the system structure for temporal cloaking, avoids the drawbacks of easy detection, easy decoding and easy analysed brought by linear modulation system, and then strengthen the safety and reliability in signal transmission. Theoretical analysis and experimental results validate the proposed system. The proposed method and achieved results indicate potential application in secure communications and data multiplexing subject to channel bandwidth requirements.

Design and Implementation of a New Architecture of a Real-Time Reconfigurable Digital Modulator (DM) Into QPSK, 8-PSK, and 16-PSK on FPGA

One of the prerequisites of Electronic Warfare (EW) is to have the means to provide secure point-to-point wireless data and voice communications with other ground stations. New technologies are giving rise to bigger information security threats. This situation illustrates the best the urgency of reducing the development and upgrade time of EW systems. Previous works suggest that digital systems are the best candidates for this purpose and therefore form the backbone of modern Electronic Warfare. Indeed, Digital Modulation (DM) techniques are widely used in modern wireless communication systems. This is largely due to their high resistance to noise and their high transmission capacity that can be achieved through data multiplexing. In this article, a new reconfigurable architecture of a Phase Shift Keying (PSK) modulation is described. The latter can be configured in real time to produce the following modulation schemes: QPSK, 8-PSK, and 16-PSK without having to regenerate the FPGA configuration bits. This action can be done by software via programming or manually using a DIP switch. The proposed design is implemented on the Xilinx xc7k325tfbg900 FPGA using the Genesis 2 development board. The Vivado Physical Design Automation tool indicates a power consumption of 303 mW by the on-chip circuit. The experimental results are in agreement with the simulations.

Design and Implementation of a New Architecture of a Real-Time Reconfigurable Digital Modulator (DM) Into QPSK, 8-PSK, and 16-PSK on FPGA

One of the prerequisites of Electronic Warfare (EW) is to have the means to provide secure point-to-point wireless data and voice communications with other ground stations. New technologies are giving rise to bigger information security threats. This situation illustrates the best the urgency of reducing the development and upgrade time of EW systems. Previous works suggest that digital systems are the best candidates for this purpose and therefore form the backbone of modern Electronic Warfare. Indeed, Digital Modulation (DM) techniques are widely used in modern wireless communication systems. This is largely due to their high resistance to noise and their high transmission capacity that can be achieved through data multiplexing. In this article, a new reconfigurable architecture of a Phase Shift Keying (PSK) modulation is described. The latter can be configured in real time to produce the following modulation schemes: QPSK, 8-PSK, and 16-PSK without having to regenerate the FPGA configuration bits. This action can be done by software via programming or manually using a DIP switch. The proposed design is implemented on the Xilinx xc7k325tfbg900 FPGA using the Genesis 2 development board. The Vivado Physical Design Automation tool indicates a power consumption of 303 mW by the on-chip circuit. The experimental results are in agreement with the simulations.