SBIR Phase I: Feasibility of Chiral Fiber Polarizer

这个小型企业创新研究(SBIR)第一阶段项目旨在展示基于手性光纤的新型光纤内偏振器和偏振转换器的可行性。当非圆形纤芯的光纤通过微型烤箱时，螺旋双折射被赋予这些光波导。因此，手征光纤光栅(CFG)不需要对用于加工光纤Bragg光栅(FBG)的光敏玻璃进行相干照射，而是由专门准备的玻璃预制件通过一种通用的连续工艺产生。它们是真正的光纤器件，不需要任何基板、散装部件或刚性包装。偏振器和偏振转换器都将基于间距为数十微米的CFGs。这些基于CFG的器件将以极低的成本制造，将允许根据应用要求在宽或窄的光谱范围内控制具有高消光比的透射光的偏振。它们将在通信、偏振模色散(PMD)补偿、波分复用(WDM)和法拉第旋转器等方面有广泛的应用。偏振器也是陀螺仪等依赖光学干涉的传感器的关键。偏振和频率选择性手性光纤的应用范围从电信到传感。在高带宽光纤通信中使用外部调制器要求入射光波被线偏振。这就需要使用偏振器，因为电信中使用的激光光源通常具有随机偏振。此外，偏振保持光纤的任何使用都需要将偏振光发射到光纤中。偏振器也是偏振模色散补偿系统中的关键部件。多功能手性偏振器可以由耐火或耐辐射玻璃制成，以便它们可以在具有高水平辐射、高温或腐蚀性化学物质的恶劣环境中发挥作用。

This Small Business Innovation Research (SBIR) Phase I project is to demonstrate the feasibility of a new class of in-fiber polarizers and polarization converters based upon chiral optical fibers. Helical birefringence is imparted to these optical waveguides by twisting fibers with noncircular cores as they pass through a miniature oven. Thus thesechiral fiber gratings (CFGs) do not require coherent irradiation of photosensitive glass, which is used to process fiber Bragg gratings (FBGs), but rather are created in a versatile continuous process from specially prepared glass preforms. They are true fiber devices and do not require any substrates, bulk components, or rigid package. Both the polarizer and polarization converter will be based on CFGs with a pitch of tens of microns. These CFG-based devices, which will be fabricated at dramatically reduced cost, will permit the control of the polarization of transmitted light with high extinction ratio over broad or narrow spectral ranges as dictated by the application. They will have broad application in telecommunications to polarization mode dispersion (PMD) compensation, wavelength- division multiplexing (WDM), and Faraday rotators. Polarizers are also key to sensors relying on optical interference such as gyroscopes.Polarization and frequency selective chiral fibers have applications ranging from telecommunications to sensing. The use of external modulators for high bandwidth fiber telecommunication requires that the incident wave be linearly polarized. This necessitates use of a polarizer since laser sources used in telecommunications generally have random polarization. Further any use of polarization maintaining fiber requires that polarized light be launched into the fiber. Polarizers are also key components in PMD compensation systems. The versatile chiral polarizers may be fabricated from refractory or radiation resistive glasses so that they may function in harsh environments with high levels of radiation, high temperature, or corrosive chemicals.