780nm Short-wavelength PM optical fiber

Idealphotonics' Panda and Bowtie single-mode polarization-maintaining (PM) optical fibers are named according to the type of stress rod used. The stress rod is aligned with the fiber core, and the applied stress generates birefringence within the core, maintaining polarization. The Panda-type stress rod is cylindrical, while the Bowtie-type uses a trapezoidal prism stress rod, as shown in the diagram above. Generally, these two types of fibers can be used interchangeably. Panda-type fibers have long been used in the communications field because the cylindrical stress rod is easier to maintain uniformity over long distances during production. Polarization-maintaining (PM) fibers are designed to provide the highest level of polarization maintenance for wavelengths from 488nm to over 1550nm. These fibers can be used in interferometric sensors, modulators, delay lines, spectroscopy, and biomedical applications. We use "Bowtie" stress-applying components (SAP) to induce birefringence in the fiber core. These efficient SAP designs can generate very high birefringence without excessive stress, thus effectively controlling the polarization orientation throughout the fiber system. The Bowtie PM fiber core has high-expansion, boron-doped glass regions on both sides, which shrink more than the surrounding silica. The resulting tension creates birefringence (producing two different refractive indices: a higher refractive index parallel to the applied stress and a lower refractive index perpendicular to the stress). Fibercore's "Bowtie" design generates more birefringence than any other stress application design. This is because it is based on two opposing wedges, which is the simplest and most effective way to apply stress to a point.