Germanium Laser Power Converters at 1550 nm with Efficiencies Over 30%

Germanium laser power converters—devices that convert laser light into electrical power via the photovoltaic effect—offer attractive cost advantages, particularly at 1550 nm, a wavelength that provides eye safety, atmospheric transparency, and efficient laser operation. This paper presents the design, fabrication, and characterization of improved Ge‐based laser power converters that have achieved record efficiencies of 30.8% at an input power of 6.7 W/cm 2 . We analyze the current advancements and limitations of these converters and provide a roadmap for achieving efficiencies exceeding 39%, demonstrating the expanding role of photovoltaic Ge devices beyond conventional solar cell applications.