Experimental Demonstration of a Coherent Receiver that Visualizes Longitudinal Signal Power Profile over Multiple Spans out of Its Incoming Signal

DSP-Based Link Tomography for Amplifier Gain Estimation and Anomaly Detection in C+L-Band Systems

“…For more information, see https://creativecommons.org/licenses/by/4.0/ employed in current commercial optical systems, a central and open question in the optical communication community is: how to efficiently distribute monitors across complex networks in a cost-effective way in order to capture wavelength-resolved, spatially-distributed information [13]? Recently, several monitoring features have been obtained by solely exploiting receiver (Rx) digital signal processing (DSP) modules [14]- [18], thus minimizing the requirements of distributed node-level measurement devices. The popularity of these Rx-based OPM approaches is due in part to their capability of unveiling multi-span link properties, such as longitudinal power profile [14], [15], frequency response of bandpass filters [16], span-wise chromatic dispersion mapping [17] and Raman gain [18].…”

“…Recently, several monitoring features have been obtained by solely exploiting receiver (Rx) digital signal processing (DSP) modules [14]- [18], thus minimizing the requirements of distributed node-level measurement devices. The popularity of these Rx-based OPM approaches is due in part to their capability of unveiling multi-span link properties, such as longitudinal power profile [14], [15], frequency response of bandpass filters [16], span-wise chromatic dispersion mapping [17] and Raman gain [18]. One successful example of such application was introduced in [14], where the authors proposed an in-situ power profile estimator (PPE) that reconstructs the channel power evolution along the link with sub-km resolutions [15].…”

“…The popularity of these Rx-based OPM approaches is due in part to their capability of unveiling multi-span link properties, such as longitudinal power profile [14], [15], frequency response of bandpass filters [16], span-wise chromatic dispersion mapping [17] and Raman gain [18]. One successful example of such application was introduced in [14], where the authors proposed an in-situ power profile estimator (PPE) that reconstructs the channel power evolution along the link with sub-km resolutions [15]. An insightful application that we foresee from this technique is that by overlaying the in-situ PPE from multiple WDM channels it is possible to create a distancewise, wavelength-dependent link tomography [13].…”

“…In this contribution, we experimentally investigate the application of a Rx-DSP approach (hereafter named link tomography) to extract the spectral gain profile of C+L-band Erbium-doped fiber amplifiers (EDFA)s and detect soft-failures, such as gain tilt and narrowband gain compression. The construction of the link tomography is based on the utilization of the in-situ PPE [14], [15], which is per se a suitable approach for any optical band (including the traditional C-band), but has been specifically used in this work for C+L-band systems. This is demonstrated by running a single-channel experimental campaign in a C+L-band setup over 280 km of single mode fiber (SMF).…”

Performance Monitoring for Live Systems with Soft FEC and Multilevel Modulation

“…Another important topic is to distinguish the noise from amplified spontaneous emission (ASE) and nonlinear noise, such as broadband four-wave mixing under nonlinear fiber-optic transmission [12], which has been studied extensively [13], [14]. Very recently, data-analysis-based power profile estimation over multiple spans was demonstrated [15].…”