Ultrawide bandwidth single-mode polarization beam splitter based on dual-hollow-core antiresonant fiber

Multi-core anti-resonant hollow core optical fiber

We report the fabrication and characterization of a multi-core anti-resonant hollow core fiber with low inter-core coupling. The optical losses were 0.03 and 0.08 dB/m at 620 and 1000 nm, respectively, while the novel structure provides new insights into hollow core fiber design and fabrication.

Compact single-polarization coupler based on a dual-hollow-core anti-resonant fiber

A compact single-polarization (SP) coupler based on a dual-hollow-core anti-resonant fiber (DHC-ARF) is proposed. By introducing a pair of thick-wall tubes into a ten-tube single-ring hollow-core anti-resonant fiber, the core is separated into two cores to form the DHC-ARF. More importantly, by introducing the thick-wall tubes, dielectric modes in the thick wall are excited to inhibit the mode-coupling of secondary eigen-state of polarization (ESOP) between two cores while the mode-coupling of the primary ESOP can be enhanced, and thus the coupling length (Lc) of the secondary ESOP is greatly increased and that of primary ESOP is reduced to several millimeters. Simulation results show that the Lc of the secondary ESOP is up to 5549.26 mm and one of the primary ESOP is only 3.12 mm at 1550 nm through optimizing fiber structure parameters. By using a 1.53-mm-long DHC-ARF, a compact SP coupler can be implemented with a polarization extinction ratio (PER) less than - 20 dB within the wavelength range from 1547 nm to 1551.4 nm, and the lowest PER of - 64.12 dB is achieved at 1550 nm. Its coupling ratio (CR) is stable within 50 ± 2% in the wavelength range from 1547.6 nm to 1551.4 nm. The novel compact SP coupler provides a reference for developing HCF-based polarization-dependent components for use in the high-precision miniaturized resonant fiber optic gyroscope.

Short dual-core GaAs photonic crystal fiber splitter with a broad bandwidth and ultrahigh extinction ratio

Microstructured polarization beam splitters (PBSs) have attracted much interest in recent years. Here, a ring double-core photonic crystal fiber (PCB) PSB (PCB-PSB) with an ultrashort, broadband, and high extinction ratio (ER) was designed. The effects of the structural parameters on the properties were analyzed by the finite element method, which revealed that the optimal length of the PSB was 19.08877 µm and the ER was -324.257d B. The operating bandwidth for an ER of less than -20d B is 440 nm, and the wavelength range spans the full E+S+C+L+U band between 1,320 and 1,760 nm. The fault and manufacturing tolerance of the PBS was demonstrated for structural errors of ±1%. Moreover, the influence of temperature on the performance of the PBS was determined and discussed. Our results show that a PBS has excellent potential in optical fiber sensing and optical fiber communications.