Abstract: An optical gate array includes a photodetector, an optical modulator, and a reflecting structure arranged therebetween. The photodetector, the optical modulator, and the reflecting structure are composed of semiconductor materials. The photodetector includes an MQW (Multi Quantum Well). The reflecting structure is constituted by a distributed Bragg reflector formed by alternately stacking semiconductor layers having different refractivities. The photodetector and the optical modulator are arranged to receive light from different directions. The modulation characteristics of the optical modulator are controlled by the intensity of light radiated on the photodetector. The reflecting structure connects the photodetector and the modulator electrically and isolates lights radiated on both parts. A plurality of optical gates, each constituted by the photodetector, the optical modulator, and the reflection structure, are two-dimensionally arranged.