| 摘要 |
PURPOSE:To obtain a seal which scarcely causes an optical loss and has a high stability by providing a seal part which takes a thermal factor and an optical quality into consideration, on a boundary wall penetrating part being in different physical and chemical conditions. CONSTITUTION:Areas A, B are under physically and chemically different conditions, and are isolated by a boundary wall 11. An optical waveguide for transmitting optical information is led into the area B from the area A and vice versa. A penetrating part is formed on the boundary wall 11, an optical waveguide 12 is led in, and a seal part 13 is formed on the outside circumferential part. As for an optical refractive index of a seal material, that of a value which is below an optical refractive index of the surface of the optical waveguide is used, and as for a coefficient of thermal expansion, it is set to a value between coefficients of thermal expansion of an optical waveguide material of the optical waveguide 12 and a boundary wall material of the boundary wall 11, by which the amount of a thermal strain which is the cause of an optical loss can be reduced. When light is made incident to a substance whose refractive index is small from a substance whose refractive index is large, light which is made incident by an incident angle exceeding a critical angle is totally reflected. Light which escapes from the optical waveguide generates a component which is totally reflected between the seal part and the surface of the optical waveguide and is made incident to the optical waveguide again, and the amount of loss of light is reduced remarkably. |
