Optical Performance Monitoring of Multiple Parameters in Future Optical Networks

Optical performance monitoring (OPM) is an important tool to facilitate the management of future optical fiber communication networks. OPM measures the states of the physical layer and provides feedback to the network controller for performing tasks such as link diagnosis and fault detection. OPM exists either as standalone devices integrated in the intermediate nodes, or it could be a set of algorithms running in devices such as the optical transceivers. A more effective network controller requires OPM to monitor multiple parameters in order to perform better network planning. However, this is considerably challenging for OPM at the intermediate nodes in consideration of cost efficiency, dynamic range, monitoring accuracy, etc. Here we show that, by using a pair of low-bandwidth coherent receivers and two local lasers, a multiparameter OPM at the intermediate nodes can be constructed. It is capable of scanning the optical spectrum, measuring the optical power, wavelength, and the optical signal-to-noise ratio (OSNR). Furthermore, by exploiting the spectral correlation properties of the modern communication signals, it can also monitor chromatic dispersion (CD), polarization-mode dispersion (PMD), baudrate, and timing phase. In more specific scenarios, it can also perform polarization tracking and modulation format identification. We provide the digital signal processing (DSP) details for estimating the optical parameters. Furthermore, we demonstrate the experimental results of a real-time prototype implementing all the essential parts of our proposed OPM.