Optimum operating conditions of a Si-based power over fiber system for high power conversion efficiency at 915 to 976 nm

Research into optical fiber as an alternative medium for power transmission has accelerated in recent years, driven by advancements in laser diodes, fiber optic cable manufacturing, and semiconductor device production. These advancements have increased the feasibility and cost-effectiveness of power-over-fiber (PoF) systems. However, optimization efforts on the PoF mechanism are required to ensure the sustainability of this technology. The overall electrical-to-electrical conversion efficiency of the Si-based PoF system has not been comprehensively studied. This study investigates the optimal combination of PoF components by focusing on Si-based systems within the 915- to 976-nm wavelength range and 1- to 18-W optical power range to maximize the overall efficiency. Various combinations of laser diodes at 915-, 940-, and 976-nm wavelengths were paired with multi-mode fiber (MMF) with a 105-μm core size. Nine distinct PoF systems were evaluated based on three key parameters: attenuation, photovoltaic power converter (PPC) conversion efficiency, and overall efficiency. The findings demonstrate that 4.08 W of electrical power output at PPC is produced when 54.3 W of electrical power is supplied to the high-power laser diode in a Si-based PoF system, resulting in an overall electrical-to-electrical conversion efficiency of 7.51%. It was observed that the transmission efficiency of fiber starts decreasing at an optical power of 10 W, whereas the conversion efficiency of PPC peaks at 27.18% with an optical power input of 7 W. These results offer insights into the variation of optical power wavelengths from 915 to 976 nm and illuminate trends in power loss within PoF systems across the 1- to 18-W optical power input range. The results serve as a valuable reference for the design and evaluation of PoF systems for practical applications and technological advancement.