| 摘要 |
PURPOSE:To obtain an optical modulating element without generating diffacted light by forming flatly the surface of a layer in contact with a thermoeffect medium. CONSTITUTION:An insulator layer 12 is provided on a substrate 11, and heating resistors 13a-13d are deposited by evaporation thereon, then an insulator layer 14 is deposited by evaporation thereon. The surface of the layer 14 is polished until the surface is made flat, and a light reflection layer 15 having excellent heat conductivity such as Ta is provided thereon. A thermoeffect medium 16 and a protective plate 17 are provided thereon. When, for example, 13b among the resistors 13a-13d is selected to generate heat, the heat is transmitted through the layer 14 and layer 15 adjacent to the resistor 13b to the medium 16 and a refractive index distribution 18 is generated in said region. Said distribution is annihilated when the resistor cools with lapse of time. The time lapse cycle is in kHz order and incident light is modulated according to the input heating signal to the resistors 13a-13d. Since the surface of the layer 15 adjacent to the medium 16 is made flat, no diffracted light is generated and the light modulation with a high SN ratio is made possible. |
