| 摘要 |
PURPOSE:To form and to eliminate a three-dimensional waveguide at the lower part of a heater by laminating a substrate 1 having a refractive index n1, a layer 2 formed on the substrate 1 and having a refractive index n2, a layer 3 formed on the layer 2 and having a refractive index n3, and a strip-like heater 4 formed on the layer 3. CONSTITUTION:The refractive index n3 has a positive pitch to temperature T and the relation between the refractive index nm of a medium covering the substrate 1, the layer 2, the heater 4 and the layer 3 and the refractive indexes n1, n2 is n2>n1.nm. Namely, light is shut in the layer 2 held between the substrate 1 and the layer 3 to form a slab waveguide (even if n3>n2, the light is shut in the layer 2 by selecting the thickness of the layer 3). When current is supplied to the layer 3, the temperature of the heater 4 is increased at a part immediately under the heater 4, the refractive index of the part is increased and the effective refractive index of the layer 2 part is also increased. The light is shut in the layer 2 also in the plane direction, so that three-dimensional waveguide is formed. Thus, a switching speed and power consumption can be selected independently of the thickness of the waveguide by changing the thickness of the waveguide by changing the thickness of the layer 3 to change heat capacity. |
