L-serinium picrate monohydrate (LSPM) is an efficient nonlinear optical material with higher SHG efficiency, molecular flexibility, less lattice strain, thermal stability, high transparency and a reasonable optical band gap. Hence, the present work focuses on the growth and characterization of the LSPM single crystal. Single crystals of LSPM were successfully grown by slow evaporation technique. The grown crystal was subjected to XRD, FTIR, Optical absorption, Photoluminescence and thermal studies to understand the structural, lattice strain, optical and thermal properties of the material, and to correlate them with the NLO response. The grown crystal is found to possess a monoclinic system with non-centrosymmetric space group P2(1). Finally, the Kurtz-Perry powder technique was carried out to confirm the SHG efficiency of the material required for device fabrication.
In this simulation study, two identical laser devices are considered as if they represent a single laser device; the intent is to overcome limitations in simulation software, OptiSystem 21. Operating parameters for these two devices are selected to be the same. The study simulated the self-mixing nonlinear effect by optical feedback via single-mode optical fiber by following the Lang-Kobayashi model. Results for observed spectroscopy related to laser dynamics during self-mixing are included for large-scale fiber lengths (5, 10, and 15 km); this is to be able to employ sensing in harsh environments. Variations in signal parameters included polarization degree and state, which in practice arise with fiber bend and twist, resulting in birefringence and subsequently different group delay. They are considered in the experiment to control chaotic dynamics. Results confirmed effectiveness for suggested signal parameter variations by giving rise to laser dynamical chaoticity specifications. Calculated Correlation Dimension is fluctuated from 2.8158 to 3.1564 which approves the chaoticity for results. Accordingly, the observed spectrum bandwidth was changed to be 10 GHz with a fiber length of 5 km and 45 degrees of polarization. The increase in chaotic signal bandwidth (BW) was reduced to 8.6 GHz at a 10 km optical fiber length and 0 degrees polarization. As for 15 km, the bandwidth reached 8.6 GHz at-90 degrees of polarization. These variations in laser spectrometry indicated more efficient sensors based on the high sensitivity property of chaotic dynamics. Such a novel sensor needs less complicated interferometry.
Free-space optical (FSO) communication is a green wireless data transmission technique that utilises light beams as a modulated carrier and is known for its high capacity. Numerous advantages of FSO technology include compatibility with unlicensed frequency bands, reduced latency, inexpensive installation costs, and large bandwidth. Because of this, it can be used for both the first and last terminal connections. However, weather-induced attenuation, especially from rain, fog, and haze, can weaken the signal-to-noise ratio (SNR) and restrict the performance of FSO systems. This work proposes a MIMO-FSO (Multiple-Input Multiple-Output FSO) system coupled with double-and triple-boost optical amplifiers to improve transmission quality and signal power, thereby addressing these issues. The system's performance is evaluated at three standard wavelengths - 850 nm, 1310 nm, and 1550 nm-using non-return-to-zero (NRZ) modulation. Experimental results show that a 32 & times;32 MIMO configuration with a triple-stage amplifier at 1550 nm achieves a maximum transmission distance of 114.8 km under clear weather conditions. The system maintains operable ranges of 14.84 km in rain, 10.48 km in fog, and 8.32 km in haze in unfavourable environments. The system's dependability across various atmospheric conditions is confirmed by thorough evaluations of the Q-factor, bit-error rate (BER), and eye diagrams.
This work introduces an integrated single-mode fiber, free space and visible light communication links in next-generation passive optical network (PON) enabled orthogonal frequency division multiplexing as well as optical code division multiplexing. The results reveal reliable fiber, FSO and VLC range of 100 km, 2800 m and 20 m, respectively, at an aggregate data rate of 2Tbpsunder critical climate and turbulence. Also, it offers acceptable power penalties of 1-2 dB with maximum power budgets of-26 dBm and-39 dBm receiver sensitivity with 12 dB insertion loss. The comparative literature underscores its advantage over other designs in terms of code implementation and overall design.
Radar systems rely on effective sidelobe suppression to concentrate energy on the primary lobe, ensuring accurate target detection and minimizing false identifications. In both military and civilian applications, sidelobe reduction plays a crucial role in enhancing precision by mitigating clutter and environmental interference. Uncontrolled sidelobe allow unwanted reflections from structures, water surfaces, and terrain, introducing noise that degrades radar sensitivity. To address this, polyphase codes are optimized using a hybrid optimization algorithm that integrates particle swarm optimization (PSO) and the gray wolf optimizer (GWO). MATLAB was utilized in the simulative analysis and optimization process. This approach combines the global search efficiency of PSO with the local refinement capabilities of GWO, achieving superior sidelobe suppression while preserving resolution and detection accuracy. The proposed method enhances radar performance by reducing interference, improving target discrimination, and increasing resilience against jamming, making it a robust solution for modern radar applications. Optimization of P4 polyphase code using genetic algorithm yields a maximum signal-to-noise ratio of 21.91dB for Tukey window. On the other hand when the P4 polyphase codes are optimized using PSO and gray wolf algorithm then for Tukey window, signal-to-noise ratio of 31.78dB is achieved. Our results shows that hybrid algorithm performs better than the other algorithms in terms of signal quality.
