This paper introduces a new topology of multilevel inverter, which is able to operate at high performance. This proposed circuit achieves requirements of reduced number of switches, gate-drive circuits, and high design flexibility. In most cases fifteen-level inverters need at least twelve switches. The proposed topology has only ten switches. The inverter has a quasi-sine output voltage, which is formed by level generator and polarity changer to produce the desired voltage and current waveforms. The detailed operation of the proposed inverter is explained. The theoretical analysis and design procedure are given. Simulation results are presented to confirm the analytical approach of the proposed circuit. A 15-level and 31-level multilevel inverters were designed and tested at 50 Hz.

In this paper, two-and-three channel all-optical AND logic gates based on four-wave mixing in a highly nonlinear fiber for 120 Gbps on–off keying signals were designed, simulated, and investigated. Simulation results show low bit error rate and consequently fairly high Q-factor at the receiving end in both two and three inputs AND gates, as well as the logic operation, is confirmed by the open eye diagrams with moderate power penalties for both designs.

In this paper a laser-based <span>visible light communication system for PC to PC data transmission has been designed, simulated, and implemented. This type of communication uses light waves in the visible spectrum (380 nm to 750 nm) to deliver data. Visible light communication is any way of transmitting data using visible light. In order to avoid being detected by human eyes, this kind of communication sends information at a slower rate than human vision. Visible light communication is significantly more reliable and capable of high information transmission rates than existing wireless technologies such as Wi-Fi, Bluetooth, and others that use radio frequency spectrum. Laser-based visible light communication systems are low-cost, low-power, and do not require radio interference studies. A diode laser is frequently used to create the signal carrier. Due to its high efficiency, it can transmit data as well as illuminate. Light waves can't be intercepted because they can't penetrate opaque objects, signifying a very secure connection.</span>

In this study, the high performance of dense wavelength division multiplexing (DWDM) by using a traveling wave semiconductor optical amplifier (TW-SOA) at a channel spacing of 100 GHz is investigated, in terms of (Q-factor, injected current, transmitted power, gain). The Optisystem software is employed to send the different range of input power over the different ranges of the TW-SOA injected current with optimized TW-SOA parameters. The data rate of trans- mission optical signal up to 300 Gb/s at -35 dB input signal power have been investigated. The better results have been measured of the information signal with high quality and gain, when the range of input power is corresponding to the optimized range of injected current for the signal to be transmitted effec- tively. The present communication also supports various numbers of users with the same data rate of 5 Gb/s which is used to check the high quality of the signal in the receiver.