Software has been developed using the MATLAB language to analyze laser diode having the architecture InGaAsP/InP .The cavity length of active region of multi quantum well semiconductor laser effect on threshold current, quantum efficiency and optical output power of InGaAsP/InP and separate confinement heterostructure (SCH) is investigated. High-speed communication systems, especially those that use optical fiber communication for high-speed data transmission, use lasers with a wavelength of 1.55 μm. here, the performance of changing the cavity length values of active region between 250 to 500 μm at room temperature is study in this work. The characteristics power–current (P–I)and related features, threshold current and slope efficiency have been investigated. The threshold current decreases with increase of cavity lengths because the carrier density in the quantum well is very high. This effect is particularly pronounced in the shortest cavity measured (250μm), we extractIth=6.25ma,αi=30mA and ηd=63%. These modifications show that our proposed structure is better compared to the GaInP/GaAs 5QW laser structure (Ith=360mA and ηd=51%).

In the present study, ultra-thin layer ZnS is inserted in the structure of standard solar cell between CdS buffer layer and CZTS absorber layer to represent the Second Phase (SP) often forms on the top of CZTS. The impact of this layer on the performance of CZTS solar cells is illustrated by the diverse results obtained by simulation using SCAPS-1D. The formation of ZnS on the CZTS surface has harmful effects on the solar cells parameters where the conversion efficiency (η) decreases by 2%. When varying thickness of ZnS SP of 2% to 20% corresponding of the total absorber layer the efficiency decreases by about 0.65%. The ZnS SP can deteriorate the photovoltaic power conversion efficiency from 10.2% to levels of 8.8%, depending on the material buffer layer and the thickness of ZnS SP. Using the ZnS as buffer layer mitigates harmful effects of the ZnS secondary phase forms on the top of CZTS absorber layer.