We demonstrate the existence of chaotic spiking and mixed mode oscillations sequences in the dynamics of semiconductor devices (laser diode and light emitting diode) with ac-coupled optoelectronic feedback. We eventually show that this regime is the result of an incomplete homoclinic scenario to a saddle-focus, where an exact homoclinic connection does not occur. The synchronization scenarios have been shown.
The signal coming from SiO_{2} layer of MOS structure have large noise-to-signal ratio. This has two reasons - first: the dielectric layers have small Raman efficiency, second: the thickness of the dielectric layers are of the order of 10 nm, so the volume of the material irradiated with laser light is small. At the other side spectroscopic and optical data carry the information about important properties of the structure like mechanical stress. Distribution of mechanical stress introduce an important contribution to the electric properties of the electronic systems based on the MOS structures. Therefore, it is important to "distillate" the optical data from the noise. In this contribution the authors discuss some methods of denoising of the Raman signal. The discussed methods compare treatments like wavelet analysis or convolution. The work is illustrated with some examples of the extraction of the data coming from thin layers. The examples of application of the optical data in the description of the properties of the studied structures are presented.
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