Two-way Mach-Zehnder interferometer system and polarization state adjusting method thereof

Abstract

The invention discloses a two-way Mach-Zehnder interferometer system and a polarization state adjusting method thereof. The two-way Mach-Zehnder interferometer system comprises a laser device, a first dynamic polarization controller, a second dynamic polarization controller, a first coupler, a second coupler, a third coupler, a fourth coupler, a first interference arm, a second interference arm, transmission fibers and a microprocessor. The system is simple in structure, carries out polarization state adjustment on bidirectional light through the two dynamic polarization controllers, can effectively improve polarization state adjustment speed, and has obvious effects especially under a severe environment. The polarization state adjusting method includes the steps of using long fixed step length and short fixed step length to increase drive voltage of the two dynamic polarization controllers, carrying out polarization state adjustment, and affecting visibility and phase difference. Therefore, the two-way Mach-Zehnder interferometer system effectively improves polarization state adjustment speed, and has obvious polarization state adjustment effects especially under the severe environment, the problem of sinking into endless loop is not easy to happen, and the phenomenon that the phase difference always can not be adjusted to be smaller than phase difference tolerance does not exist.

Description

technical field [0001] The invention relates to a polarization state control technology, in particular to a two-way Mach-Zehnder interferometer system and a polarization state adjustment method thereof. Background technique [0002] It is of great practical significance to timely discover and accurately locate intrusion behaviors in modern security defense systems. Traditional security defense systems mainly use camera video recognition technology, infrared sensor technology, etc. These security defense technologies have shortcomings such as short monitoring distance, weak anti-electromagnetic interference ability, and high maintenance cost. The distributed optical fiber vibration sensor can measure the vibration information of the entire optical fiber length with time. It has the advantages of long detection distance, strong anti-electromagnetic interference ability, and easy maintenance after installation. It has become the most promising application prospect in the field ...

AI Technical Summary

Problems solved by technology

This two-way Mach-Zehnder interferometer system can quickly adjust the polarization state in a good environment (signal-to-noise ratio greater than 60dB), but in a harsh environment (signal-to-noise ratio is less than 30dB), the polarization state adjustment time is too long, and there are Sometimes even the state where the phase difference is less than the phase difference tolerance cannot be adjusted all the time, this is because: when adjusting the polarization state, the two optical paths will change at the same time, if the two optical paths have a large difference in visibility, they are not in the same visibility stripe On (or near) the stripes, the phase difference of the optical signals of the two optical paths may be less than the phase difference tolerance, and the optical signal can meet the positioning requirements of the application system), and it is easy to cause the polarization state to be adjusted all the time. The phase difference is less than the phase difference state of tolerance

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