プラスチック光ファイバに描画したファイバ・ブラッグ・グレーティングの圧力依存性を解明した石川（M1）の論文が IEEE Photonics Technology Letters に掲載されました。本成果は、キプロス工科大学との共同研究により得られたものです。
R. Ishikawa, H. Lee, A. Lacraz, A. Theodosiou, K. Kalli, Y. Mizuno, and K. Nakamura, “Pressure dependence of fiber Bragg grating inscribed in perfluorinated polymer fiber”, IEEE Photon. Technol. Lett., vol. 29, no. 24, pp. 2167-2170 (2017).
We investigate the hydrostatic pressure dependence of the Bragg wavelength of a fiber Bragg grating (FBG) inscribed in a perfluorinated graded-index (PFGI-) polymer optical fiber (POF) at 1550 nm. At 0.5 MPa, the Bragg wavelength increased with time and became almost constant ~150 min later. Such a long time constant probably originates from the unique structure of the PFGI-POF, which has a thick overcladding around its core and cladding. The pressure-dependence coefficient without considering the time constant was estimated to be 1.3 nm/MPa; this is over 5 times the values of other types of POF-FBGs. This indicates that by removing the overcladding of the PFGI-POF, fast-response high-sensitivity pressure sensing will be feasible. Once the Bragg wavelength became constant at 0.5 MPa, the pressure-dependence coefficient of the Bragg wavelength was measured to be –0.13 nm/MPa, the absolute value of which was comparable to those of other POF-FBGs, but with an opposite sign.