Huawei Technologies Co., Limited

Dajiang Jin

Zhiping Jiang

Jianhong Ke

Minggang Si

Xiaodong Luo

Hong Yang

Tejia Liu

A system monitors optical performance of an optical link within an optical network. The system includes an optical transmitter having an expanded-spectrum pilot-tone modulator for modulating an expanded-spectrum pilot tone onto a high-speed data signal to generate an expanded-spectrum optical signal and an optical receiver for receiving the expanded-spectrum optical signal and for detecting and decoding the expanded-spectrum pilot tone to enable monitoring of the optical performance of the optical link.

Optical channel monitoring using expanded-spectrum pilot tone

The disclosure is directed at a method and system for optical telecommunications performance monitoring via a dual frequency pilot tone. By applying a dual frequency pilot tone, with a first pilot tone frequency selected from a low frequency band and a second pilot tone frequency selected from a high frequency band, either simultaneously or alternatively, to a wavelength channel, one of the pilot tone frequencies may be adaptively selected to improve wavelength channel monitoring. More specifically, stimulated Raman scattering (SRS) caused crosstalk and chromatic dispersion (CD) caused pilot fading which adversely affect performance monitoring of the wavelength channel may be reduced.

Method and apparatus for providing a pilot tone

Embodiments can provide spurs removal in a pilot-tone spread signal. For achieving this, at least one peak in the pilot-tone spread signal may be found. A predetermined small range of the spectra power around the at least one peak may be removed. In some situations, the removal of the spurs in the pilot-tone spread signal may result in inadvertent removal of a normal part of the pilot-tone spread signal. For addressing this, a power ratio between the spectrum of the pilot-tone spread signal before the removal and after the removal can be calculated. For accounting for the power loss due to the spurs removal, this power ratio can be applied to the pilot-tone spread signal after the removal to obtain a corrected pilot-tone spread signal.

Spur removal in pilot-tone OPM

During optical performance monitoring in low SNR conditions, the detection of pilot data may be more difficult because the detector may mistake noise for the pilot data signal. Systems and methods are disclosed herein that try to address this problem. In one embodiment, a pilot tone detector processes the received signal to determine a maximum correlation peak, and then performs tracking of the correlation peak over time. Unlike the pilot data signal, noise is typically more transient in nature. Therefore, if a correlation peak does not actually correspond to the pilot data signal, but instead corresponds to noise, then the correlation peak typically disappears over time when tracked. A search for a new correlation peak may then be performed. When a correlation peak is determined that actually corresponds to the pilot data signal, then the correlation peak typically remains when tracked.

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Sichuan, China

Dajiang Jin