Investigation of the signal enhancement of Nd3+ codoped TeO2-ZnO pedestal waveguides, at 1064 nm, due to Au nanoparticles deposited over the core is presented for the first time. Nd3+ doped TeO2-ZnO thin film was obtained by RF Magnetron Sputtering deposition. The resulting core with 500 nm height and widths in the 4-40 mu m range, exhibited low roughness average in all area measured (0.48 +/- 0.04) nm. Minimum propagation losses of 2.2 dB/cm were observed for waveguide width of 40 mu m whereas an increase took place for smaller ones. Scanning electron microscopy (SEM) allowed the waveguide structure inspection and transmission electronic microscopy (TEM) the Au nanoparticles evaluation. The results showed that the Au nanoparticles contributed up to 75 % of relative gain enhancement, under 808 nm excitation. This increase was due to the local field growth in the proximity of the nanoparticles that enhances the density of excited Nd3+. The internal gain that considers the propagation losses reached positive values for larger core widths (above 8 mu m).

The Total Solar Irradiance (TSI) is the principal energy source that propels dynamic changes within the Earth's climate system over extended periods. The variability in TSI plays a crucial role in shaping the long-term evolution of the Earth's climate. This study proposes to introduce a novel approach to investigating irradiation and advancing our understanding of solar radiation's impact on Earth's climate by leveraging circuit technology. Photonic integrated circuits (PICs) represent a pioneering breakthrough in integrating multiple optical components. In contrast to existing sensor platforms, PICs offer increased sensitivity, less interference from electromagnetic noise in measurements, and a more compact design. Most instruments in space that measure TSI are called electrical substitution radiometers (ESR). An ESR usually includes an optical absorbing element connected to a reference heat sink. A poorly conducting thermal link keeps the heat sink at a constant temperature. The instrument compares the heating caused by the radiant power absorbed with the heating caused by an electrical current. The Brazilian National Institute for Space Research (INPE) has initiated a project to create solar observational tools as part of the global effort to comprehend the workings of the Sun and its impact on Earth. The Galileo Solar Space Telescope (GSST) comprises two instrument designs - Irradiance Monitor Module (IMM) - to accomplish the mission objectives. One of the tools is a small radiometer constructed on a photonic integrated circuit. The primary objective of this research is to mitigate instrument uncertainty and elevate temperature measurement techniques in radiometers. By exploring innovative ideas and approaches, this work seeks to redefine state-of-the-art temperature quantification within these crucial scientific instruments. A key aspect of our methodology involves implementing a new instrument design utilizing Mach Zehnder Interferometer (MZI) technology embedded in a substrate for temperature detection. Adopting photonic circuits is a pivotal strategy to provide a more direct and durable solution to temperature sensing. This approach is anticipated to minimize uncertainties associated with electronics and comparators. Here, we will showcase the results of the preliminary manufacturing outcomes. These findings contribute to the ongoing efforts to enhance temperature measurement techniques, aiming to deepen our comprehension of how the Sun's energy influences Earth. Through this work, we anticipate advancing the capabilities of radiometric instruments and paving the way for a more nuanced understanding of the Sun and climate dynamics.

Distributed Bragg reflectors (DBRs) have found applications in various fields, including optical communications, light generation, solar cells, and sensors. DBRs are also crucial in open-access Fabry‐Pérot microcavities for enhanced and spectrally tunable light-matter interactions. This document presents the inverse design, fabrication, and optical characterization of aperiodic Ta2O5/SiO2 multilayer DBR mirrors targeting a sharp reflectivity spectrum. The results were confirmed through simulations and experimental measurements. The proposed inverse design methodology can be used to develop DBRs for important technologies such as single-photon sources, polaritonic systems, and random laser generation.

In this work, we investigated a platform for real-time emulsion droplet detection and size measurement in optofluidic platforms. An 8.2 µm core diameter input optical fiber and a multi-mode Gradient Refractive Index (GRIN) output fiber were integrated into an acrylic microfluidic channel platform consisting of three layers. Water-in-oil emulsions were investigated, since relevant applications have emerged in the recent past for these types of emulsions, such as drug encapsulation as well as droplet-based Polymerase Chain Reaction (PCR) amplification of DNA, among others. The main contribution of this work is in understanding the main physical phenomena (i.e., total internal reflection, refraction, and interference) behind the complex transmittance pattern obtained for these droplets. For this purpose, a frequency domain electromagnetic wave propagation modelling of the structure using the Finite Element Method (FEM) was used along with experimental measurements.

This paper intends to make a brief presentation of in integrated circuits’ developments and efforts towards new wireless applications at the millimeter-wave frequencies band. Considering low-cost applications for the consumer market, it is shown that using only one technology is not desirable for cost and size reasons. The 3D integration becomes a necessity for the new applications in such frequencies, pushing forward alternative technologies and new 3D interconnection techniques.

In this paper we present a balun on the MnM interposer technology platform based on a microstrip to CPS transition that was designed to feed a quasi-Yagi antenna at 60 GHz. Two microstrip lines with lengths differing in half a wavelength create a phase shift of 180° from a single-ended input. The balun structure occupies an area of 0.2 mm 2 and operates in the frequency range between 67 GHz and 76 GHz. The output amplitude and phase imbalance of the balun are lower than 1 dB and 10 degrees, respectively.

In this work we present the details regarding the fabrication process of pedestal based optical waveguides, using different materials with large optical nonlinearities as core layer. With the pedestal fabrication process it is possible to use novel materials that are highly inert to chemical etchants or alloys composed of heavy metal elements, since this technique does not require etching of the core material itself. Lateral confinement of light is performed through the fabrication of pedestals by Reactive Ion Etching (RIE) on the lower cladding. The last step in the fabrication process is the deposition of the core layer and, for this reason, etching this layer is no longer necessary. The materials used as core layer are Aluminum Nitride and Titanium oxynitride films, due to the fact that these materials present a great potential for the fabrication of Nonlinear Optics integrated devices.