As societies progress, the demand for energy escalates, leading to exploration of advanced energy sources like nuclear fusion. Deuterium-deuterium fusion emerges as a promising option due to its reliance on the ample isotope deuterium found in water, offering efficient and long-lasting energy generation. The potential depletion of the deuterium-to-hydrogen ratio from fusion reactions could act as a technosignature discernible by astronomers seeking evidence of alien civilizations. Notably, the study highlights how anomalies in isotopic ratios on exoplanets could be indicators of nuclear fusion technology, detectable through advanced telescopes like the James Webb Space Telescope (JWST). Despite fusion's appeal in terms of sustainability and cleanliness, challenges like resource depletion and climate impacts arise with intensive energy consumption, necessitating careful management by civilizations. The broader exploration of technosignatures encompasses various possibilities beyond fusion-induced anomalies, demonstrating the depth of research into uncovering traces of advanced extraterrestrial life.