Influence of external factors on power transmission in few-mode optical fiber transmission lines

This research examines the influence of external physical factors on signal transmission in few-mode optical fibers (FMF), focusing particularly on parameters such as temperature (-10°C to +60°C), bending radius (<20 mm), mechanical stress (0–100 MPa), and refractive index (1.00–1.50), and their impact on power loss. The aim of the study is to analyze signal attenuation in FMFs caused by external influences and to propose technical solutions to enhance system reliability. In the Materials and Methods section, precise measurements were carried out using an OSA spectrum analyzer, a Mach-Zehnder interferometer, and power meters. For instance, power loss reached 0.35–0.4 dB/km with rising temperature. According to the results, the greatest signal attenuation was observed under mechanical stress, where power loss reached 1.0 dB, while in single-mode fibers (SMF), this value was only 0.2 dB/km. The discussion highlighted that FMF systems are capable of delivering data at speeds of ≥100 Gbit/s, making them high-performance systems; however, they also exhibit high sensitivity to external influences (rated 3/5 on the sensitivity scale). In conclusion, to ensure reliable operation of FMF systems, the implementation of vibration protection technologies, the use of adaptive modules, and maintaining a bending radius of ≥20 mm is recommended.