Eight-junction In0.53Ga0.47As laser power converters (LPCs) designed for converting the laser energy around 1520 nm are demonstrated with a maximum room-temperature (RT) conversion efficiency of 36.9 ± 0.9% at 53.9 W/cm2. Subcell photocurrents of the LPC are extracted from current steps in wide-voltage-range I–V curves, and the current mismatching degree (Cm) at RT is determined to be ∼5%. Temperature dependence of the Cm of the InGaAs LPC confirms that the LPC reaches its minimal Cm around RT. Finally, the LPCs are characterized under different temperatures and laser powers, and the temperature coefficients of the open circuit voltage and conversion efficiency are fitted to be −12 mV/K and −0.155%abs/K, respectively. The experimental results show the potential of In0.53Ga0.47As multijunction LPCs for applications in free space and fiber-based long distance laser power transmission.