Fig. 1. Development of optical fiber polarization measurement technology

Fig. 2. Measurement schematic diagram of the optical frequency domain interferometry^[51]

Fig. 3. Schematic diagram of the optical frequency domain measurement for polarization crosstalk of a polarization maintaining fiber^[52]

Fig. 4. Noises vary with the optical power

Fig. 5. Variation of dynamic range^[52]. (a) Effect of the wavelength sweep range; (b) effect of the wavelength sweep rate; (c) effect of the optical path difference

Fig. 6. Relationship diagram of OFDP measurement performance

Fig. 7. Dynamic range limit model of the OFDP system^[51]. (a) Dynamic range fitting results (color background image) and the measurements (black dots) under corresponding condition; (b) verification of inflection point induced by the frequency sweep nonlinearity characteristic

Fig. 8. Experimental results for the envelope detrending method^[65]. (a) Influence of different auxiliary interferometer OPDs on the corrected SFDR; (b) envelopes of main interferometer signal before and after correction; (c) correction results for severe signal mismatch

Fig. 9. Point spread functions of OFDP system with and without distortion correction^[65]

Fig. 10. Measurement principle of CPI method^[70]. (a) Experimental setup; (b) schematic diagram of principle; (c) phase noise elimination process

Fig. 11. Compensation result of CPI method^[70]. (a) Results of case 2 with and without ambient noise; (b) result comparison of case 1 without ambient noise and case 2 with ambient noise

Fig. 12. Typical commercial instrument for polarization measurement of optical fiber. (a) Luna ERM-202; (b) Santec PER-340; (c) Photonetics WIN-P400; (d) FiberPro ICD800; (e) Luna PXA-1000; (f) HEU OCDP; (g) GDUT OFDP-I

Fig. 13. Calibration of OFDP system. (a) Calibration optical structure; (b) calibration results

Fig. 14. Test optical path of OFDP^[51]

Fig. 15. Distributed polarization crosstalk measurement results of a LiNbO₃ waveguide modulator and the point spread function of the OFDP system^[52]

Fig. 16. Dynamic range with optimized parameters^[51]. (a) Optimized dynamic OFPD range with various sweep rates and optical path differences; (b) polarization crosstalk measurement results of optimized Y-waveguide

Fig. 17. Long polarization-maintaining optical fiber measuring applications^[78]. (a) Comparison of OCDP and common-path OFDP; (b) measurement result of an 9.8 km ultra-long distance polarization-maintaining optical fiber

Fig. 18. Test results of fiber sensing coils. (a) Distributed polarization crosstalk measurement result (-40‒-20 ℃); (b) low temperature abnormal crosstalk generation process; (c) polarization crosstalk as a function of temperature