Power-Over-Fiber System With Intermittent Operation Based on Capacitor Voltage Estimation for High-Efficiency Energy Charging

We propose a power-over-fiber system with a new photovoltaic converter voltage control technology consisting of intermittent operation of a light source based on capacitor voltage estimation to achieve high energy efficiency. This efficiency is made possible by ensuring the photovoltaic converter voltage stays within an appropriate range. However, detecting and controlling the voltage on the photovoltaic converter side would waste power. In our system, a controller on the light source side estimates the voltage of photovoltaic converter side from our circuit model and controls the photovoltaic converter voltage by controlling light source activation/deactivation. Therefore, it is possible to maintain high photoelectric conversion efficiency without wasting power on the photovoltaic converter side. We show that this method can significantly improve energy efficiency from 11.0% to 22.4% compared to a method that controls the voltage on the photovoltaic converter side. We also demonstrate that an optical switch with a power consumption of 130 mW can be driven with 5-mW optical input. Our power-over-fiber system is practical because its optical power is low and safe enough to be used in existing optical access networks.