OSNR (Optical Signal To Noise Ratio) monitor based on polarization multiplexing signal

Abstract

The invention provides an OSNR (Optical Signal To Noise Ratio) monitor based on a polarization multiplexing signal. The monitor comprises a pump light unit (102), a coupler (101), a polarization controller (103), an annular device (104), a polarization beam splitter (105), a faraday rotation unit (106), a highly nonlinear fiber (107) and an adjustable filter (108), wherein an optical signal output by the pump light unit (102) and a polarization multiplexing optical signal satisfy a cascading four-wave mixing effect generating condition; and the faraday rotation unit (106) generates 90-degree polarization rotation. The monitor provided by the invention utilizes a highly nonlinear environment structure to successfully eliminate a polarization rotation effect existing in a polarization multiplexing system, and the aim of utilizing one monitoring device to accurately monitor the OSNRs of two cross-polarization channels respectively is realized. The monitor provided by the invention can be applied to a high-speed optical switching network to monitor and evaluate the signal quality in real time so as to discover potential faults of the network, and further, the normal operation of the optical network can be ensured.

Description

technical field [0001] The invention relates to the technical field of optical devices, in particular to an optical signal-to-noise ratio monitor based on polarization multiplexing signals. It is suitable for monitoring the optical signal-to-noise ratio of mutually orthogonal polarization channels in a polarization multiplexing system, and can realize network functions such as optical parameter amplification and wavelength conversion. Background technique [0002] In the past ten years, the optical transmission rate in the backbone network has increased rapidly, and the transmission capacity has also been greatly improved through dense wavelength division multiplexing DWDM. Advanced modulation forms such as PSK and PDM have also been increasingly used in optical networks. Therefore, in order to manage such a high-capacity optical transmission system and switching system, and prepare to grasp the current signal quality problems, optical performance monitoring is essential. S...

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Problems solved by technology

However, using this method to achieve OSNR monitoring of multiple channels requires multiple measurement devices, so it is not suitable for DWDM systems; (2) Based on the structure of high nonlinear fiber plus power detectors, this scheme uses the excited Brillouin scattering effect, this scheme can be applied to OSNR monitoring of PDM signals in WDM systems, but the measured OSNR will be affected by polarization mode dispersion or chromatic dispersion; (3) Based on narrowband optical filtering and RF spectrum analyzer structure , this way can realize PMD, CD insensitive OSNR monitoring

However, since many parameters may affect the radio frequency spectrum of the signal, this method needs to know a lot of prior information of the original signal to be able to monitor accurately

In addition, all the above methods simply monitor the OSNR of the PDM signal as a whole. In fact, factors such as PDL in the transmission of the signal will cause the OSNR of the two polarization states to be unequal, so (4) based on digital signal processing DSP) structure, through the optimization algorithm, the orthogonal polarization state in the polarization multiplexing signal is processed separately, and the optical signal-to-noise ratio monitoring that is not sensitive to polarization mode dispersion and chromatic dispersion can be realized, but its processing rate is limited by the "electrical domain bottleneck". limited and not suitable for high-speed switched networks

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