Design of all-optics reconfigurable GRIN (Gradient-Index) planar structure for crossover and parallel interconnects will
be presented. Design represents a unique combination of GRIN materials, simple geometry optics and waveguide
technology for both parallel and distributed processing and communication networks. The optical analysis is based on-axis
and off-axis multiple imaging property of GRIN components. The analysis includes the study of the Point Spread
Function (PSF) for describing the performance of the GRIN planar structure and the evaluation of the Space Bandwidth
Product (SBP) for estimating the number of channels which can be handled. The dependence of the number of channels
on the wavelength of the light and the aperture of the planar interconnect is shown. The results are given for five
working wavelengths of Laser Diode (LD) and for four transverse aperture of reconfigurable optical interconnect.
The correspondence between the linear integral transform and the ray-transfer matrix of a diffraction-free first-order optical system is used to describe the ray trajectory and to study the point spread function (PSF) in an active GRIN microlens characterized by a complex refractive index. The results show that the active microlens is regarded as a lossless microlens with a Gaussian mask induced by the complex refractive index. Comparison between light propagation effects in passive and active GRIN microlens is outlined.
We present the laser backwriting process on glass by laser ablation of metal targets, in order to fabricate waveguides on pyrex glasses. An horizontal position of the sample and the plate was found suitable to improve the effect of the plume in the sample with respect to the alternative vertical arrangement. We have analysed the longitudinal and transversal profiles, using a profilometer and have compared the results for the different laser sources used, speeds and metal targets. We have analyzed the refractive index profile of the samples obtained, in order to evaluate the change in the substrate due to the metal ablation. A cleaning of the surface and a heat treatment of the glass has been made in order to improve the results.
We present the fabrication of waveguides by laser ablation of metal targets on pyrex glasses. An horizontal position of the sample and the plate was found suitable to improve the effect of the plume in the sample with respect to the alternative vertical arrangement. We have analysed the longitudinal and transversal profiles, using a profilometer and have compared the results for the different configurations, speeds and metal targets. We show pictures of the surfaces, obtained by electron microscopy and confocal microscopy. We have studied the characteristics of the structures taking account the optical and thermal properties of the metal foils.
We present a hybrid optical device for measurement of refractive index variation in a selfoc lens by the Talbot effect. The intrinsic nature of the device that combines a linear grating and an inhomogeneous medium permits to measure changes in the refractive index along the axis as a function of the position shift of the first self-image. Possible changes in the temperature during lens fabrication can be extracted from refractive index variation. The hybrid device has a refractive index sensitivity of ±7 x 10<sup>-5</sup> per nanometer of position shift of the first self-image.