Zhang Wei, Webb David J
Opt Lett. 2014 May 15;39(10):3026-9. doi: 10.1364/OL.39.003026.
The humidity response of poly(methyl methacrylate) (PMMA)-based optical fiber Bragg gratings (POFBGs) has been studied. The characteristic wavelength of the grating is modulated by water absorption-induced swelling and refractive index change in the fiber. This work indicates that anisotropic expansion may exist in PMMA optical fiber, reducing the humidity responsivity of the grating and introducing uncertainty in the responsivity from fiber to fiber. By pre-straining a grating, one can get rid of this uncertainty and simultaneously improve the POFBG response time.
对基于聚甲基丙烯酸甲酯（PMMA）的光纤布拉格光栅（POFBG）的湿度响应进行了研究。光栅的特征波长通过光纤中吸水引起的膨胀和折射率变化进行调制。这项工作表明，PMMA光纤中可能存在各向异性膨胀，这降低了光栅的湿度响应率，并在不同光纤之间的响应率中引入了不确定性。通过对光栅进行预应变，可以消除这种不确定性，同时提高POFBG的响应时间。
