High-Efficiency 1064 nm Metamorphic Photonic Power Converters for Spacecraft Wireless Power Transfer

Laser energy transmission is becoming an attractive technology for innovative space mission concepts. Highly efficient photonic power converters are key elements to enable new applications of optical power transmission in the space domain. In this regard, III-V semiconductor materials are perfect candidates for the realization of these devices because the material band gap can be tuned and optimized for a specific laser operating wavelength, thus boosting the overall energy conversion efficiency. At Fraunhofer ISE, we have developed various absorber materials with suitable band gap energies optimized for common laser operating wavelengths. In this paper, we report on the first results of a metamorphic GaInAs photonic power converters optimized for 1064 nm operations, a wavelength at which several space-based laser systems operates. An unprecedented equivalent monochromatic conversion efficiency of 54.7 % is demonstrated at an irradiance level of 14.2 W/cm 2 for begin-of-life conditions. These results highlight the potential of optical energy transmission systems for future space applications targeting high conversion efficiencies.