Optics and Photonics Society of Iran

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The effect of RW length and taper angle on the beam quality and threshold current density of a SQW Al_0.07Ga_0.93As 808 nm high power tapered laser diode is investigated by simulation. Results in an output optical power of 1 W shows that in taper angle of 3°, M2 factor is about 3 and in wider angles (4,5,6) ,in RW lengths of 500, 750 and 1000 μm, is increased with the slope of 0.21, 0.18 and 0.08 respectively. Threshold current density is linearly decreased in wider taper angles from 850 to 630 (A/cm²), from 730 to 570 (A/cm²) and from 520 to 330 (A/cm²) in laser diodes with RW lengths of 500, 750 and 1000 μm respectively.

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In this paper, the effect of interface engineering in the construction of a planar perovskite solar cell was simulated. For considering the interface between active layer and adjacent layers, the two layers IL1 and IL2 were added to the conventional structure of the solar cell, due to the surface roughness created during the fabrication. As the most important property in optical investigations, the dielectric function of two interface layers, were estimated by the Bruggeman effective medium theory. The effect of the thickness of IL1 and IL2 layers on the efficiency of perovskite solar cell was investigated by using TMM theory and FDTD simulation for this developed model. The results show that the thickness of the IL1 and the IL2 layers have a severe effect on the parasitic absorption of the active layer, which should be considered in the formation of planar perovskite solar cell.
 

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High power semiconductor laser modulation is of great practical importance. Extensive research has been done to produce high energy short pulses. In this study by using an asymmetric structure, the optical field is shifted to n-section and the internal loss of the laser is reduced. This reduction in loss, and also applying high refractive index layers in n-section and increasing photon lifetime, makes it possible to use the gain switching method to generate several picoseconds optical pulses in edge emitting lasers. In this study, by investigating the appropriate pulse function, the maximum current limit is investigated and finally a short pulse of 80 ps (FWHM) and optical power of 3.2 W is created.