Study On Error Analysis And Suppression For The Measurement Of Distributed Polarization Crosstalk

White light interferometers,which is based on optical coherence domain polarimetry(OCDP)technology,are widely used to measure distributed polarization crosstalk due to high resolution,long distance,and large dynamic range.Polarization crosstalk reduce the signal-to-noise ratio and accuracy of measurement systems.The distributed polarization crosstalk can display the position and the crosstalk coefficient of the crosstalk point.Therefore,it is important to measure distributed crosstalk with high accuracy.However,the measurement accuracy is limited by several factors such as the high-order interference peak,noise,excessive crosstalk,interference signal overlap.These factors reduce the measurement accuracy of distributed polarization crosstalk.To improve the measurement accuracy of distributed polarization crosstalk,this paper has carried out some research work,including polarization crosstalk coupling model,polarization crosstalk measurement error suppression,and testing of polarization device.The contents include:Firstly,a simulation model of polarization crosstalk coupling is designed.The model divides the device into several basic units,and each basic unit consists of a coupling area and a transmission area.Based on the Jones matrix,the expression of light in a basic unit is given.Then,a digital propagation light path is proposed to simplify the expression of the simulation signal.As a result,the interference signal can be simulated by a computer.Experimental results prove that the model can be used to simulate the experimental results and identify the first-order interference signals in the results.We believe that the model is helpful for the improvement of polarization crosstalk measurement.Secondly,we analyzed the influence of noise,excessive crosstalk and interference peak superposition on polarization crosstalk measurement.Polarization crosstalk is calculated by calculating the power of interference peak.Error sources affect the measurement accuracy of power.The relationship between measurement error and error sources is demonstrated.The experimental results show that we can reduce the influence of error sources.After suppressing the influence of error factors,the measurement accuracy of distributed polarization crosstalk can reach 0.1 dB.Thirdly,Y-waveguide and polarization maintaining fiber were tested.Using the simulation model,we can see the meaning of each interference signal.Using error suppression method,we can correct the experimental results.After model analysis and error suppression,we can accurately and efficiently quantify the characteristic parameters of the deviceIn summary,the simulation model and error suppression method proposed in this paper can suppress the influence of error factors such as high-order interference phenomenon,noise,excessive crosstalk,and interference signal overlap.As a result,the measurement accuracy of distributed polarization crosstalk can reache 0.1 dB.Finally,we believe that the research work in this paper is beneficial to the improvement of performance of polarization device.