Bending characteristic analysis and improvement of fusion splice between photonic crystal fiber and single mode fiber

We report a study of bending characteristic analysis and improvement of fusion splice between the photonic crystal fiber (PCF) and the single mode fiber (SMF). The poor bending characteristic of the splice between the PCF and the SMF is a threat to the fiber optic gyroscope (FOG). However, the tensile strength test shows that the splice should be able to withstand a much smaller bending radius. To solve this problem, we adopt three-dimensional (3D) X-ray imaging to acquire the accurate structure of the splice and conclude that the stress concentration leads to the poor bending characteristic of the splice. A simple fiber tapering method is proposed to improve the bending characteristic of the splice without compromising the splice loss. The improved splice method for PCF has been used in FOG for space application successfully.