| 摘要 |
PROBLEM TO BE SOLVED: To provide a wavelength variable optical fiber which is capable of easily changing a Bragg wavelength by a low-voltage driving even in the tension impression by a piezoelectric element and is small in size and simple. SOLUTION: This wavelength variable optical fiber is made finer in the outer peripheral part of an optical fiber by etching and is provided with a grating structure in the core section made finer, thereby, a great displacement can be obtained with smaller tension and the period of FBGs can be highly efficiently changed. In addition, liquid, such as liquid paraffin, is filled to the circumference of the core section from which the clad section of the optical fiber is removed and the effective refractive index of the FBGs is changed by controlling the temperature of the liquid, by which the wavelength variable optical fiber filter making it possible to obtain a significant frequency change is realized. |
