An interferometric method to study the induced variations of nonlinear parameters in bent optical fiber such as third-order susceptibility (chi)~(3) and second-order refractive index n_(2) is presented. Due to the expected nonlinear response of the Young's modulus of fiber material, the profiles of asymmetric variations of the two parameters with curvature are observed and calculated, revealing the high spatial and index resolution of the method. The investigation is done in single-mode optical fibers at the standard operating wavelengths of 1300 and 1550 nm and at radii of curvature from 5 to 11 mm. At the minimum radius of curvature R velence 5 mm, the cladding (chi)~(3) velence 4.131 X 10~(-15) esu on the tensile side, whereas on the compressed side it is 4.601 X 10~(-15) esu for lambda velence 1300 nm. On the tensile side n_(2) velence 1.09 X 10~(-13) esu, whereas on the compressed side it is 1.216 X 10~(-13) esu. For lambda velence 1550 nm, the cladding (chi)~(3) and n_(2) on the tensile side are 3.96 X 10~(-15) esu and 1.055 X 10~(-13) esu, whereas in the compressed cladding side they are 4.435 X 10~(-15) esu and 1.174 X 10~(-13) esu, respectively. At lambda velence 1300 nm and R velence 5 mm, the core (chi)~(3) is given by 4.631 X 10~(-15) esu on the tensile side and 4.649 X 10~(-15) esu on the compressed side. The asymmetry in n_(2) is given by 1.223 X 10~(-13) esu on the tensile side and by 1.227 X 10~(-13) esu on the compressed side. With lambda velence 1550 nm, the core (chi)~(3) asymmetry is given by 4.46 X 10~(-15) esu on the tensile side and by 4.477 X 10~(-15) esu on the compressed side. For n_(2) its asymmetry is provided by 1.181 X 10~(-13) esu on the tensile side and by 1.185 X 10~(-13) esu on the compressed side.
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机译：提出了一种干涉法研究弯曲光纤中非线性参数的诱发变化，如三阶磁化率（chi）〜（3）和二阶折射率n_（2）。由于纤维材料的杨氏模量具有预期的非线性响应，因此可以观察和计算两个参数随曲率的不对称变化曲线，这表明该方法具有很高的空间分辨率和折射率分辨率。该研究是在标准工作波长为1300和1550 nm且曲率半径为5至11 mm的单模光纤中完成的。在最小曲率半径R velence 5 mm时，包层（chi）〜（3）velence在拉伸侧为4.131 X 10〜（-15）esu，而在压缩侧为4.601 X 10〜（-15） esu用于lambda velence 1300 nm。在拉伸侧，n_（2）速度为1.09 X 10〜（-13）esu，而在压缩侧，n_（2）速度为1.216 X 10〜（-13）esu。对于λvelence 1550 nm，拉伸侧的包层（chi）〜（3）和n_（2）为3.96 X 10〜（-15）esu和1.055 X 10〜（-13）esu，而压缩包层为分别是4.435 X 10〜（-15）esu和1.174 X 10〜（-13）esu。在λ速度1300 nm和R速度5 mm时，芯（chi）〜（3）由拉伸侧的4.631 X 10〜（-15）esu和压缩侧的4.649 X 10〜（-15）esu给出。 n_（2）中的不对称性由拉伸侧的1.223 X 10〜（-13）esu和压缩侧的1.227 X 10〜（-13）esu给出。 λvelence为1550 nm时，核（chi）〜（3）不对称性在拉伸侧为4.46 X 10〜（-15）esu，在压缩侧为4.477 X 10〜（-15）esu。对于n_（2），其不对称性在拉伸侧为1.181 X 10〜（-13）esu，在压缩侧为1.185 X 10〜（-13）esu。
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