The effect of the structural disorder in the Raman scattering of the coupled plasmon - LO phonon modes was studied in doped AlxGa1-xAs/Si alloys. The asymmetry in the Raman lines allows us the observation of these modes because the translational symmetry of the crystal was destroyed. The analysis of the position and shape of their spectral lines provides information on the concentration of carriers and the effects of structural disorder of the material. We note that the effective concentration of carriers in Raman measure differs from the nominal values given by the manufacturer, which suggests possible losses in the evaporation process of the silicon or the excess of evaporation time. The results were verified by measurement of Capacitance versus Voltage for two samples.

We present an introduction about the theoretical design of an Erbium doped fiber amplifier more known by its acronym in English as EDFA. We analyzed the gain of the amplifier as a function of the pump laser power (1480 nm and 980 nm) and size of fiber doped with Er3+.

We have measured both the irradiance distribution and the spatial propagation profiles of a light emitting diode and a HeNe laser using several experimental technique. The experimental value of the waist laser was verified using the ABCD array law at the laser case.

In this work we used a simple Michelson interferometer to characterize the deformation of a piezoelectric material in function of voltage and frequency. We obtained the piezoelectric quality factors parameters, such as, the resonance frequency, the damping constant and the quality factor by simulating its behaviour like a driven oscillator.