| 摘要 |
PURPOSE:To obtain an optical circuit which functions as an optical demultiplexer by the formation of thin film only by providing a region for separating wavelength permitting the transmission of light having at least one wavelength selectively from light in a specified wavelength region. CONSTITUTION:A second clad layer 41 of a low refractive index is formed on a semiconductor substrate 40 comprising a material having a high refractive index, and a resonance reflecting clad is formed by forming a first clad layer 42 of a high refractive index on the clad layer 41. A core section 43 for propagating light beams is formed by covering a transparent dielectric layer having a lower refractive index than the refractive index of the layer 42 on the clad layer 42. The light to be transmitted is reflected totally at an interface between the core section 43 and an air layer. The light is reflected simultaneously by the interference in the resonance reflecting clad between the core section 43 and the semiconductor substrate 40, and propagated in the core section 43. The reflectance of the resonance reflecting clad to the light propagated through the core depends on the refractive index of the clad layers 42, 41, film thickness of the layers, refractive index of the core section 43, film thickness thereof, and the wavelength of light to be transmitted. By selecting above-described factors appropriately, the reflectance may be regulated to almost 1. |
