Experiment study on measurement of the optical fiber refractive index based on digital holography

The characteristics of optical fiber are quite important for improving the performance in various application of the optical fiber including communication and sensor systems. Based on optical Mach-Zehnder interferometer, a new measuring method of optical fiber refractive index profiling using digital holography is proposed in this paper, which simplifies the experimental setup compared to traditional holography. Several kinds of fiber samples such as multimode fiber, polarization-preserving fiber and special fiber are tested and their holograms are recorded by CCD. After filtering of the hologram, the phase distribution of fiber sample can be reconstructed and extracted. At last the experimental results of refractive index profiling of fiber are given.