Research On Automatic Detection Technology Of Optical Isolator Performance

As a non reciprocal device that only allows one-way transmission of light waves,optical isolator can effectively eliminate the adverse effects caused by reflected light in the optical path,so it is widely used in all kinds of optical systems.The main indexes to measure the performance of optical isolator are insertion loss and isolation.In the actual production process,people usually use linearly polarized light to detect these two indexes;However,this method is not only inefficient,but also has errors caused by manual operation,so it is not suitable for large-scale detection tasks.In order to solve these problems,this paper studies the automatic detection technology of polarization dependent optical isolator performance,and designs an optical path system that can realize automatic measurement.The main work is as follows:Firstly,according to the polarization characteristics of light,the working principle of free space polarization dependent optical isolator is analyzed by Jones matrix method,and the measurement optical path model based on traditional linear polarization method is established.Then,through the calculation of the model,the possible measurement errors caused by manual operation are analyzed.In order to eliminate this error,the feasibility of using circularly polarized light for automatic measurement of optical isolator is discussed,and the optical path model of circularly polarized light measurement is established.By comparing the calculation results with the optical path model of linear polarization measurement,the feasibility of using circular polarization for measurement is demonstrated.Then,in order to realize the simultaneous measurement of insertion loss and isolation,a bidirectional measurement optical path is designed based on the circular polarization measurement optical path model.By testing and comparing the key indexes such as coupling efficiency and linear skewness,the debugging of the whole measuring optical path is completed,and the corresponding control module is designed based on the optical path,so as to realize the automatic performance detection system of the whole optical isolator.Finally,a batch of optical isolators are tested with this system,and the measurement results are compared with the factory data and the measurement data of linear polarization measurement system.The results show that the measurement error of the system can be reduced to 0.07 d B and the average measurement time can be reduced from 5.99 s to 2 s.It is proved that the system has good measurement accuracy and can greatly improve the measurement efficiency.