An in-fiber Mach-Zehnder interferometer is proposed for the discrimination of strain and temperature. The sensor is based on two cascaded standard single mode fibers using three peanut tapers fabricated by simple splicing. The cascaded structure excites more frequency components, which induce four sets of interference dips in the transmission spectrum. One set of the spectrum dips have different sensitivities to temperature and strain from those of the other three. The sensor can discriminate strain and temperature by monitoring the wavelength shifts of two spectrum dips. Repeated experiments are taken both for strain and temperature increasing and decreasing scenarios. Experimental results show that Dip 1 has an average strain sensitivity of -0.911 pm/με and an average temperature sensitivity of 49.98 pm/℃. The strain sensitivity for Dip 2 is negligible and its average temperature sensitivity is 60.52 pm/℃ The strain and temperature resolutions are ±3.82 με and ±0.33 ℃.

提出了一种空气孔辅助型偏振保持少模光纤，在椭圆环芯中心引入一个椭圆形空气孔，并在水平和竖直方向分别引入4个不同尺寸的圆形空气孔，以提高模式间的有效折射率差，实现多阶模式间无串扰偏振保持传输。通过数值仿真研究了4个圆形空气孔的尺寸和位置、环形纤芯的尺寸和椭圆率以及椭圆形空气孔的尺寸和椭圆率对偏振保持传输性能的影响。经过参数优化设计，所提光纤在1520～1600 nm波段内满足所有相邻模式间的有效折射率差Δn_eff均高于1.0×10^－4，色散为17.6～51.3 ps/(nm·km)。所提光纤在大容量空分复用通信技术中具有良好的应用前景。

现代光网络需要满足高速、大带宽，大容量传输技术。基于反谐振反射光波导机制，提出一种偏振保持（PM）空芯光纤。光被正交方向上厚度不同的4个套管限制在空气芯子中来实现有效的PM传输。为了实现提高PM性能的同时降低传输损耗，研究了套管中反谐振层的数量、套管厚度、空气芯子尺寸以及正交方向上相邻两个套管之间距离的影响。数值仿真结果表明，所提出的反谐振空芯光纤在1550 nm处支持两种正交偏振模式，HE_11x和HE_11y模式的双折射为1.2×10^-4，传输损耗分别为0.002 dB/m和0.013 dB/m。此外，在1425~1725 nm（带宽为300 nm）内，光纤的双折射不低于1.0×10^-4，传输损耗在0.002 dB/m~0.185 dB/m范围内，色散值低于45.51 ps?nm^-1?km^-1)。同时，由于采用空芯结构的设计，光纤具有较低的弯曲损耗。所提出的光纤在需要短距离，大容量和低时延传输的数据中心和金融网络系统等领域具有较好的应用前景。