Iraqi Laser Society Journal

This study addresses the classification of laser dyes and nanocomposites that are mixed with polymeric materials, as they are compounds that occupy a scientific position in laser applications and are of great importance in various applications. This review addresses the different types of laser dyes and the wavelengths at which they operate, as well as the polymers used in them, focusing on their thermal sensitivity, in addition to nanomaterial composites. The study included a review of previous research that is studied in this field and its review, especially studies that explore the areas of sustainable development and the practical applications of renewable energies aimed at improving the efficiency of solar cells and gas sensors. In this review, the properties and details of the wavelengths of laser dyes and different types of polymers were studied, and the sensitivity of these polymeric compounds to the heat added to them was addressed. In addition, the polymeric compounds were classified into groups according to their use, thus obtaining more accurate details about the process of improving methods of searching for more effective and more suitable materials in practical applications.

Weather conditions, such as dust, rain, and fog, significantly reduce the power of the laser used to transmit optical signals by altering the propagation characteristics of the light path. This degradation impacts the reliability and quality of free-space optical communication systems. This research aims primarily to develop a simple and intelligent solution to compensate for this atmospheric attenuation using a two-layer artificial neural network (ANN). Unlike conventional systems that rely on complex optical compensation mechanisms, the proposed ANN-based approach provides an efficient, less equipment-intensive alternative.
The process entails simulating various disturbance circumstances with MATLAB to simulate the behavior of genuine free-space channels. Experimenting with different attenuation levels in dust, rain, and fog conditions yields a dataset. This data is then used to train and test the neural network, which learns to forecast how much laser power is needed to maintain and improve signal integrity. The simulation program uses a 1550 nm wavelength and a 10 dB power factor to ensure accurate modeling. Key assumptions include the network's capacity to generalize attenuation patterns and recover the best power for transmission.

Fiber optic communication technology is essential for transmitting data at high speeds over long distances. To increase transmission capacity and quality, it is essential to use technologies that enhance these capabilities. This study investigates modulation techniques in optical fibers, including frequency modulation (FM), amplitude modulation (AM), and phase modulation (PM). The Optisystem program is used to perform design studies and analysis on a simulation model of an optical fiber communication system.
The system is equipped with a transmitting laser, 1550 nm wavelength, 20 dBm input power, and optical fiber (single mode). Modifications are analyzed and compared to achieve the highest efficiency. Two parameters are also studied: quality factor (QF) and bit error rate (BER). The results of amplitude and frequency modulation (AM and FM) techniques in optical fibers shows that FM performs best in terms of signal quality and BER, followed by AM. Phase modulation (PM) performs less effectively over long distances.

Communication and health care sensors have contributed greatly to patients and medical workers, through first, with the existence of the Covid-19, the hospital beds are unlikely to meet all infected patients, as communication and health care sensors can be used to monitor the patient's vital signs such as (temperature, pressure, Electrocardiogram..) in the hospital wherever the patient is and can be used as an automatic pandemic transmission of an alert signal from the personal servant to the emergency center by monitoring the changes in the vital signs of the individual. Secondly, to connect patients with 24-hour caregivers via the network according to the patient's needs. Thirdly, it can be used to monitor stable chronic patients who have been discharged from hospitals at home as not every patient can afford a home visit by nurses or doctors. An optical fiber sensor for monitoring the vital signs of the patient had been submitted; the temperature had been chosen to be measured. In this research the experimental and simulation by using opt-system program was done. Two different types of optical fiber were chosen as a sensing media; Fiber Bragg Grating FBG (1550nm wavelength, 20nm band width, and 10-3 w power) and single mode fiber (SMF), water bath which used to measure the temperature by FBG or SMF sensor for (36–40) C0. The Optical Spectrum Analyzer (OSA) recorded the input and output spectra. Then the results send as data using Free Space Communication System. The submitted sensors show a very good sensitivity towards temperature, for FBG sensor, the sensitivities 10.5 pm/ C0 and -8.5 pm/ C0 while the sensitivity for SMF sensor 5 pm/ C0 and -5.5 pm/ C0 for heating and cooling temperature respectively.

In this study, a heterodyne detection system is designed and constructed to detect the wavelength shift between the reference and sensing signals that results from temperature changes. A laser diode 1550 nm optical source is employed as a reference arm. While the sensing arm is represented by Erbium Doped Amplifier Fiber (EDAF). Fiber Bragg Grating (FBG) is used as a tunable element to generate different wavelengths according to the change in temperature. The Optical Spectrum Analyzer (OSA) displays the intermediate signal (beat signal) which, represents the difference between reference and sensing signals. As the temperature rises, the wavelength shifts linearly to a longer wavelength, whereas the wavelength shifts toward shorter wavelengths with the decrease in temperature. In the temperature range of (30-80) degrees Celsius, from the linear relation of beat (intermediate) wavelength and beat frequency versus the temperature, wavelength Sensitivity (WS) and Frequency Sensitivity (FS) as well as the resolution for heterodyne detection system in the case of heating and cooling, are analyzed and calculated.

Plastic pollution is currently a global challenge, with plastic waste increasingly accumulating due to weak enforcement and the absence of safe disposal practices. This research aims to explore innovative solutions for effective waste management using advanced infrared technology. The study uses a Bruker attenuated total reflection spectrometer (400-4000) cm-1 and an infrared laser (805) nm to analyze six random samples of plastic waste (juice and milk cartons). The results demonstrate that infrared analysis of strong absorption peaks (400-1800) cm-1, specifically infrared spectroscopy and laser, is able to accurately identify plastic types based on their unique spectral signatures, speeding up the sorting process and improving purity. Laser results also indicate the appearance of strong plastic peaks at 12.500 cm-1. The study highlights the advantages of infrared technology compared to conventional sorting methods and discusses the technical challenges that may face its implementation in recycling facilities. The research relies on a methodology that combines theoretical study and practical application, analyzing data from academic sources, and applying the technology to real-world models. This study identified effective formulations for several types of polymers (polyethylene, polypropylene, polystyrene, and polyvinyl chloride (PVC)), with only PE and PP being recyclable. This study aims to provide practical and effective solutions for plastic waste management and contribute to the development of a sustainable circular economy.