OSNR Monitoring Based On Four-Wave Mixing Effects

The arrival of the information age makes the demand for broadband application services continue to increase, therefore, the conventional communication mode can not meet the requirements. Today’s optical network is developing toward the intelligent, high-speed and dynamic direction. However, the use of the reconfigurable optical add-drop multiplexer (ROADM) and dense wavelength division multiplexing (DWDM) technology enables the monitoring and maintenance for network systems are more complex. The optical signal to noise ratio (OSNR) monitoring, which plays a dominant role in the optical performance monitoring, developed from traditional out-band OSNR monitoring to the in-band OSNR monitoring with a higher monitoring precision. This paper studies the in-band OSNR monitoring technique based on four-wave mixing.In this article, firstly, we introduce the basic principles of some mature out-band OSNR monitoring techniques and in-band OSNR monitoring techniques. Besides, their working conditions, advantages and disadvantages are discussed here. According this, we studied the in-band OSNR monitoring method based on four-wave mixing, which is suitable for the next-generation intelligent optical network. Then, we demonstrated the working principle of OSNR monitoring and simulated it using the Optisystem software. The monitoring range of the simulation based on single-pump FWM is about0-15dB while based on dual-pump FWM is approximately0-20dB. After the fiber length and pump power being optimized, the monitoring range is17dB and22dB respectively.