Control method and system for realizing polarization stability

Abstract

The invention discloses a control method and system for realizing polarization stability, and belongs to the technical field of optical fiber communication and optical fiber sensing. According to thecontrol method and system of the invention, the output light polarization state of any input light polarization state after passing through a polarization controller is rapidly adjusted to be close toany specified target polarization state on a Poincare sphere through a rapid positioning algorithm, and then the output light polarization state is further stabilized to a target polarization state through a random gradient descent algorithm. Therefore, any polarization state can be stabilized to any set target polarization state. The specific implementation system is composed of an input end polarization analyzer, an output end polarization analyzer, a calibrated polarization controller, a single-chip microcomputer and the like; the input polarization analyzer and the polarization controllerwith the calibrated phase difference and voltage relation are used for rapid positioning, and meanwhile, the output polarization analyzer is combined with the stochastic gradient descent algorithm tofinally stabilize the output polarization state to a set value. According to the polarization stability control method, the searching speed and the local extreme value avoidance are balanced, and thepolarization state can be rapidly and stably changed to any designated target polarization state.

Description

technical field [0001] The invention belongs to the technical field of optical fiber communication and optical fiber sensing, and more specifically relates to a control method and system for realizing polarization stabilization. Background technique [0002] In the optical fiber communication system, due to the bending, extrusion and other factors of the optical fiber during the optical fiber transmission process, the polarization state of the transmitted light changes dynamically and randomly, and the trajectory of the polarization state of the output light on the Poincar sphere is not a fixed one. point. For systems that require stable polarization states such as polarization multiplexing, coherent reception, and polarization state quantum key distribution, it is necessary to quickly stabilize the randomly changing polarization state into a fixed polarization state, or to generate a polarization-stabilized output light. The method Polarization stabilization is achieved by...

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Problems solved by technology

[0003] At present, there are many schemes to achieve polarization stabilization, which are mainly divided into two categories. One is to use multi-dimensional optimization algorithms, such as polarization stabilization control device and method (CN105629518A) and the document CHINESE OPTICSLETTERS COL 12 (11 ), the particle swarm optimization algorithm used in 110603 (2014), the genetic algorithm used in the document Engineering Applications of Artificial Intelligence Volume 25, Issue 4, (2012) published on February 07, 2012, and the method for improving the performance of the polarization controller and the gradient algorithm used in the device (CN102221751A), set the objective function, optimize the objective function to control the PC, and stabilize the polarization state, but these optimization algorithms are difficult to take into account the global search and search speed: or in order to avoid falling into local extremum and speed Slower, or faster but easy to fall into the local optimum and miss the global optimum; the other is to measure the input light polarization state, combine the target polarization state to calculate the control voltage of the polarization controller, and directly convert the input to the target polarization state , but this method is only proposed in theory, and there is no experimental confirmation, because in actual use, it will be affected by the calibration accuracy of the polarization controller and other polarization changes on the link, and the accuracy will decrease as time goes by, and the system stability poor

In addition, most polarization stabilization devices and methods can only stabilize any input light polarization state to a specific output light polarization state, rather than any output light polarization state

In many practical applications, it is necessary to stabilize the polarization state to any specified position on the Poincare sphere, thus limiting the practical application of these methods

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