| 摘要 |
PURPOSE:To turn on and off optical coupling and to discriminate the frequency of light, by coupling an optical fiber with a thin-film optical waveguide film by means of a magnetic fluid and electrically controlling the shape and position of the magnetic fluid by using a magnetic field. CONSTITUTION:A leakage magnetic field is produced by a magnetic pole 5 and a magnetic fluid 2 is held by the magnetic field. The magnetic fluid 2 is placed between a thin-film optical waveguide 3 and the optical fiber 1 and incident light 6 is totally reflected by the inner surface of the fluid 2 and injected into the optical waveguide 3. When the leakage magnetic flux from the magnetic pole 5 is reduced, the leakage magnetic flux hardly reaches the magnetic fluid 2 and the shape of the fluid 2 changes from a semicircle to an elliptic form. Accordingly, the top T of the fluid 2 becomes lower than the incident light 6 in elevation and no optical coupling takes place in such state. Therefore, turning on an turning off of the light can be made easily and, moreover, frequency separation of light which is not high in resolution can be performed by means of the angle formed by the incident light and inner surface of the magnetic fluid. |
