Experimental Crosstalk Analysis in SDM Systems with Multimode Fiber Geometry Mismatch
The crosstalk performance of different 50μ m GIMMFs with 45 spatial modes is studied using a packaged multi-plane light converter and a 96×96 optical switch for full cardinality characterization. The impact of combining different refractive index geometries and of environment-induced perturbations are addressed.
Network Design in Multiple Non-Overlapping Paths within Quantum Key Distribution Networks
The increasing demand for secure communication makes quantum key distribution (QKD) a compelling technology, as it exploits the fundamental principles of quantum physics to enhance secure data transmission. However, practical deployment faces limitations such as limited transmission distances and dedicated hardware-channel requirements. This paper proposes a linear programming-based model that jointly addresses routing, wavelength assignment, and trusted-node minimization in QKD networks with wavelength division multiplexing (WDM), considering that the secret key rate becomes impractical beyond a given transmission distance, thus requiring the relaying of secret keys through trusted repeaters. In particular, the study contrasts scenarios where traffic is concentrated along a single route with those where key rates are split and routed over multiple nonoverlapping paths (MNOPs) using two mechanisms: Concatenate Multipart (CM) and Bitwise Product Multipath (BPM). While the literature shows that MNOPs can improve security (BPM) and improve the secret key rate (CM), we demonstrate that these mechanisms come with additional deployment costs.
Free Energy Market Transition: a Study Case of 32 Consumption Units in Brazil
Given the growing consumption for energy, electricity represents a significant share in the public budget, particularly for the Government of Espírito Santo, approximately 12.46% of the total administrative expenses of the units. Based on this, the present study analyzes the feasibility of migrating Consumer Units of the Executive Branch of the State of Espírito Santo to the Free Contracting Environment, aiming for economic and sustainable gains. Thirty-two units were selected for a case study, based on consumption and demand data between 2024 and 2025, to project future consumption and costs. The analysis considered 32 Consumer Units, including the procurement of 1.25 MW average from conventional and renewable energy sources, indicating a potential savings of up to 30.54%. Although there are challenges characteristic of public administration, in contrast to management in the private sector, particularly due to national and subnational legal frameworks to which it is subject, the results indicate that migration is technically and economically feasible. This positions the Free Contracting Environment as a strategic alternative for optimizing public resources and meeting environmental goals, aligned with the Sustainable Development Goals and the longterm strategic plan entitled “ES 500 anos”.