Techniques to Ensure High-Quality Fiber Optic Gyro Coil Production

Abstract

A fiber coil is the most critical, yet least perfected component affecting the performance of a FOG. Coil winding is often considered an art, not a science, requiring technicians with magic skills to produce high-performance coils, mainly due to the lack of testing methods and capabilities. Numerous factors affect fiber-coil quality and performance, including the polarization crosstalk, coil asymmetry, fiber-winding tension, and properties of potting adhesives. This chapter will first discuss all winding-induced imperfections and their relationship to FOG performance. Novel testing methods and equipment for characterizing the static performances of both PM fiber coils and singlemode fiber coils are then introduced. Techniques are presented for measuring the transient properties of coils, such as coil asymmetry, and the Shupe effect. Finally, 3D coil inspection is demonstrated by using optical coherence tomography (OCT). With the aid of these test capabilities and associated manufacturing procedures, high-quality coils can be consistently produced for high-precision FOGs. It is now possible to claim that FOG coil winding is no longer an art but a science and can meet the demanding requirements for mass production and deployment of high-precision FOGs for various applications.