| 摘要 |
PROBLEM TO BE SOLVED: To provide a variable wavelength constitution in an optical filter in which an optical fiber having Bragg gratings is arranged in a circular shape. SOLUTION: An optical fiber 5 having Bragg gratings is installed in the circle shaped groove for installing a fiber 2 of a fiber holder 1 and a pressurization fiber 6 is installed in the inner side of the groove 2 of the obliquely upper part of the inside of the circle of the optical fiber 5 so as to be in contact with the fiber 5 and, moreover, a pressurizing plate 3 is arranged so as to cover the whole of the pressurization fiber 6 and the plate 3 is fixed to the holder 1 with screws 4. In this constitution, the controlling of the wavelengths is performed by changing the grating pitch of an optical filter (the grating area of the optical fiber) while making tension stress act in the longitudinal direction of the optical fiber 5 by minutely increasing the radius of the circle of the circle shaped optical fiber 5 while adjusting the tightening of the screws 4 fixing the pressurizing plate 3. |
