Nd:YAG laser welding of stainless steel 304 for photonics device packaging

Although pulsed Nd:YAG laser welding has been widely used in microelectronics and photonics packaging industry, a full understanding of various phenomena involved is still a matter of trials and speculations. In this research, an ultra compact pulsed Nd:YAG laser with wavelength of 1.064 µm has been used to produce a spot weld on stainless steel 304. The principal objective of this research is to examine the effects of laser welding parameters such as laser beam peak powers, pulse durations, incident angles, focus point positions and number of shots on the weld dimensions: penetration depth and bead width. The ratio of the penetration depth to the bead width is considered as one of the most critical parameters to determine the weld quality. It is found that the penetration depth and bead width increase when the laser beam peak power, pulse duration and number of shot increase. In contrast, the penetration depth decreases when the laser beam defocus position and incident angle increase. This is due to the reduction of the laser beam intensity causing by the widening of the laser spot size. These experimental results provide a reference on an optimal laser welding operations for a reliable photonics device packaging. The results obtained shows that stainless steel 304 is suitable to be used as a base material for photonics device packaging employing Nd:YAG laser welding technique

A simplified coupling power model of single mode fiber fusion at coupling length

Fabrications of single mode fiber coupling by heating fibers on a flame are very common and popular. However, controlling the output power of fiber coupling process is neither easy nor similar. Power losses occur at the coupling length due to geometrical change of the fibers after fusion. The power losses will affect sensor devices such as an optical switch. This paper proposes power splitting into the second fiber junction in terms of a new model by deriving the coupling power with two conditions of refractive index changes. First is the change in the vertical part and second is the change in the vertical and horizontal part simultaneously. Both conditions are studied by perpendicular and parallel directions. The model is examined where power absorption and reflection are accumulated by power losses. Simulation result shows that the power increases by superposition wave. These power losses are due to radiation out of the cladding and fiber heating

Investigation of laser induced inhibition and simulation in biological samples

In this research, some experimental measurements have been carried out to study the biological effects in-duced by laser irradiation on bacterial samples prepared by different ways and at different conditions. Con-sidering the induced samples, the effect of laser irradiation has been investigated through analyzing some of the properties of the transmitted and scattered laser beam for determining the stimulation or inhibition ex-perienced by the investigated sample. In this study absorbance and scattering values have been measured as indicators of sample response to the irradiation laser beam. Absorbance and scattering have been investigated for different irradiation and sample parameters. Significant responses related to inhibition and stimulation effects of the investigated samples have been obtained. These results may significantly contribute in deter-mining the effective utilization of the laser beam as a therapeutic tool for accelerating the wounds and burns healing of diabetic patients whom their response to anti-biotic is not appropriate. The simultaneous irradia-tion of samples with the use of anti-biotic shows significantly positive effect and fast response

Reconfigurable Radiation Pattern of Planar Antenna Using Metamaterial for 5G Applications

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