Capacitive Characteristics of High-Speed Photovoltaic Converters at Combined Lighting

Abstract

p–i–n GaAs photovoltaic converters of modulated laser radiation (810–830 nm) transferring both energy (laser power) and information signal were developed. The capacitance and frequency characteristics of the photovoltaic converters at a constant 0.2–1 W and variable 16 mW laser power were studied. The dependences of the heterostructures capacitance on the voltage at the p–i–n junction were obtained; it has been found out that the charge accumulated in the i-layer plays the dominant role. As a result, the decrease in the thickness of the undoped region improves the frequency characteristics. This paper shows that at the voltage in the DC circuit of 0.8 V and the laser power of 0.6 W, the efficiency of 39% can be achieved with the 450 MHz transmission band in case of the 20 mV AC signal amplitude at the load of 2.5 Ω. For the voltage in the DC circuit of 1 V in similar modes of continuous laser radiation, the efficiency was 48.6%, and the transmission band was 135 MHz. Increasing the laser power to 1 W reduced the efficiency by about 1% and the bandwidth by 30 MHz. The achieved characteristics of the studied photovoltaic converters would make it possible to use them for providing autonomous power supply for devices with low power consumption at the data rate of 100 Mbit/s and above.