Research On Polarization Dependence Of Single Mode Fiber Probe

Single-mode optical fiber probe(SMFP)is an indispensable basic component in the field of sensing and detection systems and communications.Its diversity of structural forms can adapt to different working environments,meet personalized work needs,and has a wide range of engineering applications.Among the many factors that affect the performance of SMFP,the polarization dependence is a characteristic that cannot be ignored in the light wave transmission process in SMFP.The evolution of the polarization state can be applied in the field of sensory detection to realize the field interaction between the probe and the measured object,and the polarization is related Loss will affect the quality and accuracy of the transmitted signal,so the research on the improvement of SMFP form and the problem of polarization correlation is the focus of this paper.First of all,this paper discusses two types of SMFP end face shapes,which are flat end face type(SMFP-P)and oblique octave type(SMFP-A).Each type is divided into none and lens type,and the corresponding models are constructed.Based on the eigenmode expansion method,the mode characteristics in SMFP can be analyzed in sections,and the polarization states of each mode at any point of SMFP can be characterized based on Stokes parameters and Bonga spheres.Next,the mode analysis of SMFP-P and SMFP-A is carried out.The normalized propagation constant and normalized frequency of each mode are obtained by zoning,and their changes along the propagation direction.Ten low-order mode dispersion curves and their changes are given.The evolution of the operating modes in the two types of SMFP is discussed respectively.It is found that SMFP-P has the characteristics of mode curve clusters.The transmission analysis of SMFP is carried out.The evolution of the mode field in the cross-sectional direction and the propagation direction of the two types of SMFP are discussed respectively.The normalized power curves of each mode along the propagation direction are given.Then,the evolution of SMFP-P’s polarization state along the axial center and radial fundamental mode is analyzed,and the evolution trajectory is drawn on the Bonga sphere.The evolution of SMFP-A’s polarization states along the axial and radial fundamental modes is analyzed.The similarities and differences of the polarization states of the two SMFPs are compared and analyzed,and a physical explanation is given.Finally,the polarization-dependent loss experiment of fiber jumpers based on SMFP-P and SMFP-A was carried out,the factors affecting the measurement of polarization-dependent loss(PDL)were analyzed,and the PDL test method in the field of practical engineering was introduced.Experimental results show that SMFP-A jumper has a low PDL.