A microstructure optical fiber (MOF) for co-transmission of signal and power is manufactured to provide power for remote antenna units (RAUs) and make the deployment of central stations fast and flexible. For a high laser damage threshold and a great refractive index difference, the MOF we proposed has a large core and an air ring in cladding pattern with regular holes. To realize high-quality signal transmission and flexible deployment, the MOF is made of pure silica. In this case, material dispersion, nonlinearity effects and bending loss can be restrained. Above all, the MOF with a high optical local capability and multiband optical transmission could be fabricated easily by traditional stack drawing method. Specifically, fiber loss is 2.26 dB/km at 976 nm and 1.44 dB/km at 1550 nm, acquired by the cut-back method. When the MOF was connected to a communication system with a 64-level quadrature amplitude modulation (64-QAM) 4 GHz frequency signal, an error vector magnitude (EVM) of 0.89% to 1.07% was obtained by the receiver. To the best of our knowledge, it is the first time a MOF has achieved co-transmission of signal and power. This work strongly suggests that MOF is applicable for the deployment of communication central station and emergency communication system in the future.

In this work, we demonstrated the Tm/Al co-doped silica glass fabricated by the laser additive manufacturing technology for the first time. The measurements show that the glass was doped with ${\rm{Tm^{3+}}}$ concentration of 1.64 wt% without any crystallization. The ${\rm{Tm^{3+}}}$ and ${\rm{Al^{3+}}}$ were uniformly distributed and no additional defects were introduced during the fabrication process. The glass exhibits low hydroxyl content level of 11.56 ppm. Using the prepared silica glass as the core rod, a Tm/Al co-doped photonic crystal fiber (PCF) was fabricated and performed 13.5 % slope efficiency with nearly 600 mW output laser power. This novel technology provides an alternative method to fabricate Tm-doped fiber materials with high homogeneity and large core size, promoting the further spread and development of 2 μm fiber lasers.

In this paper, a low loss and high polarization-maintaining single-mode hollow-core anti-resonant fiber (PM-HC-ARF) is designed. The elliptical core in the PM-HC-ARF is formed by strategically enlarging selected cladding air holes along the y-axis. Additionally, the variations in the wall thickness in both the x and y directions generate the distinct surface modes. By simultaneously employing an elliptical core and asymmetric core-wall thickness, we enhance the phase birefringence. Theoretical analysis results show that the proposed PM-HC-ARF achieves a transmission loss of 0.00082 dB/m at wavelength 1450 nm, along with a birefringence of 1.38 × 10⁻⁴; it demonstrates CL levels an order of magnitude below state-of-the-art polarization-maintaining HC-ARFs. Moreover, within the S+C+L+U communication bands, it achieves a bandwidth exceeding 380 nm (1420–1800 nm) while maintaining a birefringence of greater than 1.45 × 10⁻⁴. In particular, this PM-HC-ARF demonstrates a maximum higher-order mode extinction ratio of over 32,070; the single-mode transmission characteristics are excellent, along with exceptional bending resistance characteristics. When the bending radius exceeds 3 cm, the impacts on the loss and birefringence are negligible; this also demonstrates that the fiber structure shows good robustness when subjected to harsh environment interference. The proposed PM-HC-ARF is believed to have important applications in fiber optic gyroscopes, optical amplifiers, and hydrophones.

A novel hollow-core antiresonant fiber with a Bragg structure is proposed. It is numerically simulated using a commercial finite element method, and optical properties of the fiber, such as mode field, confinement loss, and bend loss, are numerically analyzed. The proposed hollow-core antiresonant fiber has advantageous optical properties, such as ultralow confinement loss, large bandwidth, and low bend loss. The structural advantage of the hollow-core Bragg antiresonant fiber also facilitates the fabrication of long-distance hollow-core antiresonant fibers. Additionally, this fiber offers potential applications in long-distance communications, data transmission, and laser power delivery.

In this paper, a low loss and high polarization-maintaining single-mode hollow-core anti-resonant fiber (PM-HC-ARF) is designed. The elliptical core in the PM-HC-ARF is formed by strategically enlarging selected cladding air holes along the y-axis. Additionally, the variations in the wall thickness in both the x and y directions generate the distinct surface modes. We have effectively enhanced the birefringence performance of the fiber structure design by introducing the combined effect of the two. Theoretical analysis results show that the proposed PM-HC-ARF achieves a transmission loss of 0.82 dB/km at wavelength 1450 nm, along with a birefringence of 1.38 × 10-4, it demonstrates CL levels an order of magnitude below state-of-the-art polarization-maintaining HC-ARFs. Moreover, within the S+C+L+U communication bands, it achieves a bandwidth exceeding 380 nm(1420-1800nm) while maintaining a birefringence of greater than1.45 × 10-4. Especially, this PM-HC-ARF demonstrates a maximum higher-order mode extinction ratio of over 32,070, the single-mode transmission characteristics are excellent. along with exceptional bending resistance characteristic. When the bending radius exceeds 3 cm, the impacts on the loss and birefringence are negligible, this also demonstrates that the fiber structure shows good robustness when subjected to harsh environment interference. The proposed PM-HC-ARF is believed to have important applications in the fiber optic gyroscopes, optical amplifiers, and hydrophones.

In this study, a tunable Tm³⁺/Ho³⁺ co-doped lanthanum aluminosilicate double-clad photonic crystal fibre laser operating in the 2 μm waveband based on Littman-type cavity using blazed grating is demonstrated. The fibre laser can demonstrate a broad tuning range from 2028 nm to 2083 nm. Such a tunable fibre laser is ideally suited for environmental monitoring, laser therapy, and remote sensing applications.