An attempt has been made to develop an optical power-feed system capable of supplying power to sensors and interfacing circuits. Laser light is transmitted to solar cells, where the optical energy is converted into electrical energy. A continuous-wave laser diode (wavelength 813 nm, maximum optical power 800 mW) is used as the light source. A laser diode with graded-index fiber coupling (400 μm core diameter, numerical aperture 0.2) is connected to eight solar cells assembled in series around the fiber end. The active area of each solar cell is 0.5 cm × 0.27 cm. The open-circuit voltage and the short-circuit current are found to be about 4.5 V and about 8.5 mA, respectively, with a laser diode optical power of 650 mW. Upon temperature measurement using this power-feed system, the modulated signal can be transmitted by a light-link diode via a step-index fiber. The results indicate that the system can be used as a power supply for conventional sensor elements.