Nitride-based semiconductor nanostructures for applications in optical comunications at 1,5 um

During the last years, there has been an increasing demand of higher optical bandwidth in optical networks. The main challenge to satisfy this demand lies in the network nodes themselves, since the electronic processing of information in these nodes is inherently bandwidth limited. These nodes should thus evolve towards an all-optical control of the information. The purpose of this thesis is to investigate the potential of III-nitride-based semiconductor nanostructures for optical communication applications at telecom wavelengths. III-nitrides cover the near infrared range with two approaches: intersubband transitions in GaN/AlN heterostructures and interband transitions in InN-based structures. The knowledge of its nonlinear optical properties is crucial for the development of novel all-optical devices to be implemented in high speed (>40 Gbps) transmission systems. The first part of this thesis describes the ultrafast nonlinear optical response in GaN/AlN quantum wells and quantum dots at 1.55 um, and proposes its application to optical devices with high switching speeds. Afterwards, the nonlinear optical response in InN bulk and highly-efficient InN/InGaN multiple-quantum wells grown by molecular beam epitaxy is addressed. The estimation of the reduction of the light speed by the slow-down factor makes these structures suitable for optically controlled delay lines. Finally, the nonlinear behaviour of InN films deposited by reactive radio-frequency sputtering is investigated at 1.55 um with view to optical limiting applications. For this aim, the influence of the deposition conditions on the quality of thin InN films deposited on Si(111) and GaN template substrates is firstly studied. In addition, the effect of using an optimized InN bulk buffer layer on the features of on top deposited thick InN films is evaluated. In conclusion, current results confirm that GaN/AlN heterostructures and InN-based technology are a very promising choice among III-V semiconductor for all-optical signal processing applications at 1.55 um