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The all-fiber voltage sensor is difficult for application because of its complex structure, difficult signal demodulation, and sensitivity to the environment. In this paper, a wavelength modulated all-fiber voltage sensor with a simple structure is designed and proposed using straight tapered single-mode fiber and stacked piezoelectric crystal as a voltage sensing unit. The simulation analysis of its performance shows that it can realize the voltage measurement of 0 kV ∼ 10.41 kV, and the accuracy can reach 0.2%. Additionally, the tapered fiber has good strain sensitivity and temperature insensitivity, and its sensitivity is up to 0.03206 nm / μ ε with low bending loss. [ABSTRACT FROM AUTHOR]

• A nonreciprocal error model of the RAOVS was established. • A significant idea was proposed to suppress nonreciprocal error. In the reflected all-optical voltage sensor (RAOVS) based on the converse piezoelectric effect, the influence of ambient temperature on the system output cannot be ignored when the length of sensing fiber and compensating fiber is asymmetric. In this study, the nonreciprocal error model of the RAOVS due to the asymmetric fiber length is originally established, according to the polarization optics theory. Then, the influence of temperature fluctuation and asymmetric fiber length on the output error is investigated with the condition of different voltage levels. Finally, a method for suppressing the nonreciprocal error is presented from the sensing fiber performance. Results show that the increase of nonreciprocal phase shift is proportional to the asymmetric fiber length and it is hardly avoided in the assembly process. And the magnitude of nonreciprocal error is influenced by ambient temperature fluctuation. Interestingly, the nonreciprocal error can be reduced by ~75 times with employing polarization-maintaining photonic crystal fiber (PM-PCF) as sensing fiber. This study can provide a theoretical basis for suppressing the nonreciprocal phase shift error of RAOVS in practically. [ABSTRACT FROM AUTHOR]

• A simple and efficient fiber optic sensor networking method that can be used for multiplexing a large number of sensors in mesh-grid topology. • Either discrete or long span distributed fiber optic sensors could be multiplexed in this network. • Self-reconfigurable topology provides sensors with more resilience in case of failures. • Centralized or discrete network control method could be determined based on actual sensor conditions. This paper presents a mesh grid topology for an optical fiber sensor network, which has an efficient structure for intelligent monitoring and reconfigurable protection operations. The integration of light sources and detectors within the network plays a crucial role in achieving comprehensive monitoring of the entire sensor network. Moreover, we have designed multiple nodes for sensing channels with distinct function to maximize the benefits of the topology in terms of network resilience. Finally, centralized and discrete signal processing schemes for network control systems have been demonstrated to be effective under various application conditions. [ABSTRACT FROM AUTHOR]

• We improve the calculation method of geometrical birefringence and gives the complete calculation process by means of thermal stress theory and polarization optics theory. • The birefringence values of the elliptical, rhombic. • We innovatively proposed a polarization-maintaining fiber with a 'leaf-shaped' core, and its birefringence value is nearly double that of the conventional Panda-type polarization-maintaining fiber. • We further optimized the fiber structure to increase the birefringence of the new 'leaf-shaped' core polarization-maintaining fiber to 7.6921 × 10 - 4 in Panda-Type polarization-maintaining fiber and 7.732 × 10 - 4 in Bow-Tie fiber. • From the perspective of practical application, the performance of the mode field is analyzed and explain the fiber fabrication method. Considering the utilizing of geometrical birefringence, we propose a new type of stress-induced polarization-maintaining fiber (PMF) with a 'leaf-shaped' core —a structure found by combining the merits of elliptical and rhombic core shapes. The finite element method (FEM) is used to compare and analyze the contribution of the elliptical, rhombic, 'star-line shaped' and 'leaf-shaped' core on geometrical birefringence. The results show that this kind of PMF improves the polarization-maintaining performance of the fiber significantly, and its birefringence value can reach 7.692 × 10 - 4 in Panda-Type PMF and 7.732 × 10 - 4 in Bow-Tie PMF which are doubled compare with the traditional Panda-Type PMF. Analysis of the mode field performance also indicates that the designed fiber is suitable for the sensing field. At the same time, this fine-diameter PMF conforms to the trend of miniaturization of current used fiber-optic sensors and can be applied to fiber optic gyroscopes. [ABSTRACT FROM AUTHOR]