| Polarization maintaining fiber is a kind of high birefringence fiber,which can be made into tunable wave plate according to its properties.The accurate matching of the phase difference of the system can be achieved,and the disadvantage that various wave plates can only provide fixed phase compensation and difficulty to match accurately is overcome,and the direct connection with the pigtail of the optical fiber transmission system is facilitated.However,the PMF’s spindle is not visible and is highly susceptible to additional stress.How to accurately find the polarization-maintaining fiber spindle direction,and apply stress in the direction of the main axis,change the phase difference between the fast and slow axis to achieve the tuning of the phase difference between the two orthogonal components of light,the phase compensation for each optical system is very important.In this paper,a tunable fiber-optic waveplate based on squeezed polarization-maintaining fiber is proposed,and a process device for directional extruding PMF in the light-transmitting state is designed to solve the difficult points of additional stress and interference,deviation from positive extrusion,etc.The process guarantee provided by the quality of the tuned fiber wave plate is also provided;a PMF autofocus lens performance test system is also designed.The content of this paper is as follows:(1)A grin-lens of PMF test system was designed to test the collimation performance and spot shape of the output spot of the grin-lens.And transform the optical power meter.Selection of high-performance grin-lenses for the production of polarized light sources in tunable waveplate systems.(2)Analysis of theory based on PMF mode coupling.Using MATLAB software to simulate the relationship between the coupling strength and the direction of the PMF subjected to transverse stress.The conclusion is drawn that the direction of the transverse stress and the direction of the PMF’s principal axis are at zero or hour and the coupling strength is minimal.Theoretical analysis uses Stokes parameters to measure the light polarization extinction ratio,and uses MATLAB to calculate the light transmission polarization extinction ratio during the polarization-maintaining fiber spindle to ensure the accuracy of the experiment.(3)The drive circuit of the tunable fiber-optic wave plate is designed so that the output voltage changes from 0-150V to control the piezoelectric ceramic.Design the circuit schematic,select the components,and use the Altium Designer software to draw the PCB board and make the board.For the design of the power supply circuit,the household AC output is stabilized at 12V DC as the system power supply.The transformer is designed and the power supply circuit and the drive circuit are integrated in the same PCB board.(4)The design and production of polarization-maintaining fiber-optic extrusion system is completed,and the focus is on eliminating the influence of additional stress.The extruder rotary table,optical fiber connector,six-dimensional micro-adjustment frame and optical fiber holder are designed.The quasi-finding PMF spindle direction experiment was completed.Polarization analyzer was used to observe the change of the polarization degree of the input light in the experiment to accurately find the direction of the PMF spindle.Record the Stokes parameters in the experiment and use MATLAB to calculate the light polarization extinction ratio during the experiment to ensure the accuracy of the experiment.The design of the aluminum box structure encases the driving circuit part and the waveplate part of the optical fiber,and uses the circuit to drive the piezoelectric ceramic to compress the polarization-maintaining optical fiber,and successfully produces a tunable optical fiber wave plate. |
PDF Full Text Request