| 摘要 |
PURPOSE:To obtain a small-size lightweight variable wavelength optical filter having excellent response and reliability with which transmission wavelength can be controlled at high accuracy. CONSTITUTION:A glass substrate 3 has a curved shape in one face and a dielectric multilayered film 4 is formed on this curved part. Light entering from outside transmits through the dielectric multilayered film 4. The glass substrate 3 can be moved perpendicular to the optical axis by a piezoelectric actuator 2 housed in a chassis. By moving the glass substrate 3, the angle of the dielectric multilayered film 4 to the transmitting light is changed and the transmission wavelength can be controlled. Since the glass substrate 3 is positioned with the piezoelectric actuator 2 at high accuracy, wavelength can be controlled at high accuracy. In this constitution, by shaping the glass substrate 3 to have a convex face on the one surface and a concave of the same radius on the other surface, angles of the incident light and exiting light to the optical axis are made equal so that the dependence of insert loss on wavelength can be decreased. |
