| 摘要 |
PURPOSE: To obtain a reflection type fiber grating filter capable of easily changing reflection wavelengths by adding a means for applying tension on an optical fiber or means for changing the temp. of the optical fiber, thereby changing the pitch of gratings and changing the reflection wavelengths of the gratings. CONSTITUTION: The section of the optical fiber 1 where the gratings 2 are formed is covered double by protective sleeves 3, 4 consisting of heat shrink tubes, etc., and an arbor 5 consisting of metals or plastics, etc., is fixedly arranged on one side between these protective sleeves 3 and 4. Compressive force acts on the optical fiber 1 and the pitch of the gratings 2 is shortened when this filter is placed on fulcra 6, 6 in such a manner that the side arranged with the arbor 5 comes into contact with these fulcra 6, 6 and side pressure 7 is applied to the filter from the side opposite to the side where the arbor 5 is arranged. The reflection wavelengths are then more shifted to the short wavelength side. The reflection wavelengths are shifted to the long wavelength side when the side pressure 7 is applied from the side arranged with the arbor 5. |
