Abstract: An anti-torsion solid-core polarization-maintaining photonic crystal fiber includes a cladding having an inner layer arranged around the core and an outer layer between the inner layer and the outer wall of the cladding. The inner layer has multi-layer air holes used to construct optical properties and two micron-size air holes arranged along the x-axis extending in the center producing form birefringence. The outer layer includes multi-layer air holes arranged radially along the y-axis. The size and arrangement of the multi-layer air holes in the outer layer cause the bending stiffness of the photonic crystal fiber along the x-axis to be different from that along the y-axis. While meeting the requirements of the optical properties of the fiber, the photonic crystal fiber possesses an anti-torsion ability due to the anisotropy of stress distribution in the radial direction, thereby reducing the non-reciprocal phase difference generated by the magneto-optic Faraday Effect.

Abstract: An anti-torsion solid-core polarization-maintaining photonic crystal fiber includes a cladding having an inner layer arranged around the core and an outer layer between the inner layer and the outer wall of the cladding. The inner layer has multi-layer air holes used to construct optical properties and two micron-size air holes arranged along the x-axis extending in the center producing form birefringence. The outer layer includes multi-layer air holes arranged radially along the y-axis. The size and arrangement of the multi-layer air holes in the outer layer cause the bending stiffness of the photonic crystal fiber along the x-axis to be different from that along the y-axis. While meeting the requirements of the optical properties of the fiber, the photonic crystal fiber possesses an anti-torsion ability due to the anisotropy of stress distribution in the radial direction, thereby reducing the non-reciprocal phase difference generated by the magneto-optic Faraday Effect.

Abstract: A hollow-core antiresonant fiber (HC-ARF) with nested supporting rings (NSRs) has a fiber structure that includes from the inside out a fiber core, a first silica antiresonant ring (SARR), a first air antiresonant ring (AARR), a second SARR, a second AARR and an external silica wall. The fiber structure further includes a first NSR within the first AARR and a second NSR within the second AARR. The HC-ARF with NSRs has advantages and benefits of low confined loss (CL), large bandwidth, simple structure and very good bending characteristics. Therefore, the application fields of HC-ARF are greatly expanded.

Abstract: A hollow-core antiresonant fiber (HC-ARF) with nested supporting rings (NSRs) has a fiber structure that includes from the inside out a fiber core, a first silica antiresonant ring (SARR), a first air antiresonant ring (AARR), a second SARR, a second AARR and an external silica wall. The fiber structure further includes a first NSR within the first AARR and a second NSR within the second AARR. The HC-ARF with NSRs has advantages and benefits of low confined loss (CL), large bandwidth, simple structure and very good bending characteristics. Therefore, the application fields of HC-ARF are greatly expanded.

Abstract: The nondestructive determination of core size of a hollow-core photonic bandgap fiber (HC-PBF) using Fabry-Perot (FP) interference is performed with an apparatus including a tunable laser source (TLS), a 1×2 single-mode (SM) coupler, an SM collimator, a six-axis translation stage, an optical detector, and an oscilloscope. The light from the TLS passes through the 1×2 SM coupler and the SM collimator to perpendicularly enter two parallel air-SiO2 interfaces of the core of the fiber and is reflected, while the TLS is tuned from one wavelength to another. Then the reflected spectrum is guided to the optical detector, where its interference intensity is converted into voltage intensity to be displayed at the oscillator and fitted with a least-squares method to obtain the distance between the two air-SiO2 interfaces. The core size of the fiber can be obtained by rotating the fiber and repeating the procedure at multiple angular positions.

Abstract: The nondestructive determination of core size of a hollow-core photonic bandgap fiber (HC-PBF) using Fabry-Perot (FP) interference is performed with an apparatus including a tunable laser source (TLS), a 1×2 single-mode (SM) coupler, an SM collimator, a six-axis translation stage, an optical detector, and an oscilloscope. The light from the TLS passes through the 1×2 SM coupler and the SM collimator to perpendicularly enter two parallel air-SiO2 interfaces of the core of the fiber and is reflected, while the TLS is tuned from one wavelength to another. Then the reflected spectrum is guided to the optical detector, where its interference intensity is converted into voltage intensity to be displayed at the oscillator and fitted with a least-squares method to obtain the distance between the two air-SiO2 interfaces. The core size of the fiber can be obtained by rotating the fiber and repeating the procedure at multiple angular positions.

Abstract: The low magnetic sensitivity PM-PCF based on mechanical buffer is obtained by adding buffer structures in the cladding layer of the photonic crystal fiber. In the center of the fiber, the core region contains at least 3 layers of air-holes, enclosed by the cladding layer. The buffer structures are placed in the cladding layer. These buffer structures are formed by replacing silica of any shape by air, and are symmetrically located in X-axis and Y-axis directions to achieve mechanical isotropy. The buffer structures improve the fiber's performance in fiber coiling and stress conditions. Therefore, the fiber optic gyroscope using the PM-PCF can do without a magnetic shield, thus greatly reducing the weight of the fiber optic gyroscope and extending the scope of its application. Compared with the conventional commercial PCF, the PM-PCF provides the fiber optic gyroscope with lower temperature sensitivity and improved accuracy.

Abstract: The low magnetic sensitivity PM-PCF based on mechanical buffer is obtained by adding buffer structures in the cladding layer of the photonic crystal fiber. In the center of the fiber, the core region contains at least 3 layers of air-holes, enclosed by the cladding layer. The buffer structures are placed in the cladding layer. These buffer structures are formed by replacing silica of any shape by air, and are symmetrically located in X-axis and Y-axis directions to achieve mechanical isotropy. The buffer structures improve the fiber's performance in fiber coiling and stress conditions. Therefore, the fiber optic gyroscope using the PM-PCF can do without a magnetic shield, thus greatly reducing the weight of the fiber optic gyroscope and extending the scope of its application. Compared with the conventional commercial PCF, the PM-PCF provides the fiber optic gyroscope with lower temperature sensitivity and improved accuracy.