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Study on the stable output method of Mach-Zehnder frequency domain depolarization system

In this paper, a series of research on the stable output method of Mach-Zehnder frequency domain depolarization system is carried out. Based on the analysis of Mach-Zehnder frequency domain depolarization technology and DOP measurement technology, it is pointed out that the instability of DOP of the depolarization system has an adverse effect on the calibration of the DOP meter with the extremum search method. It is clear that the instability problem is mainly due to the accurate alignment deviation of optical fiber. As a result, a set of solutions to improve the stability is proposed and verified by experiments. The technical core of this scheme is to extend the SOP of the depolarization system from half range control to full range control, reduce the correlation between SOP control and power control, and overcome the problem of optical fiber axis deviation in conventional technology. Through the experimental verification, the Mach-Zehnder frequency domain depolarization system based on the scheme proposed in this paper can effectively control the stability of the DOP of the output light within ± 0.1%, which can effectively calibrate the DOP meter with the extremum search method.