Recent Progress in the Characterization of the G-SNR and the OSNR of Future SDM-based Subsea Open Cables

Abstract

We characterized the G-SNR and the OSNR of an SDM-compatible submarine optical cable with different modulation formats and symbol rates up to 101 GBd, observing good agreement between all G-SNR measurements.

Accurate prediction of performance for a submarine open cable

“…The GSNR measurement is obtained through the SNRASE measurement with a transponder calibration (Q² factor is measured in back-to-back conditions for different ASE noise loading and after transmission). The uncertainty related to this measurement can reach 0.15 dB, as observed in 7 . In 15 , the authors were able to estimate and measure an SNR penalty of 0.5 dB due to GAWBS noise.…”

“…The uncertainty on ASE noise is linked to the OSA measurement. In 2 , the OSNR measurement is said to be within roughly 0.1 dB in error and in 6 , a deviation of less than 0.2 dB is observed between OSNR measurements performed with different methods. The GSNR measurement is obtained through the SNRASE measurement with a transponder calibration (Q² factor is measured in back-to-back conditions for different ASE noise loading and after transmission).…”

“…OSNR (optical signal-to-noise ratio) and GSNR (generalized signal-to-noise ratio) measurements have been chosen as metrics to describe open cables wet plant 5,6,7,8 . GSNR accounts for the total noise contributions accumulated during the optical transmission in the wet plant.…”

Employing channel probing to derive end-of-life service margins for optical spectrum services

“…The existing variations for these metrics alongside a comprehensive characterization guide using a channel probing, or otherwise known as Inverse Back-to-Back Method to characterize the submarine cables are explained in [11]. Further specifics about the test schema and achievable precision are discussed in [12]. However, terrestrial networks are often more prone to dynamic changes caused by changes in traffic load and exposure to temperature changes compared to submarine systems.…”

“…Furthermore, if the transceivers used for OSaaS characterization are not fully characterized against the performance impairments caused by test wavelength, chromatic dispersion, and polarization mode dispersion (PMD), it can cause bias in the estimations. Therefore, the exact procedure described in [11] and [12] is not often applicable in the characterization of OSaaS for brownfield terrestrial systems. However, as the multiple benefits of OSaaS outweigh the operational complications that the service model may introduce, the OSaaS characterization activity in terrestrial links is likely to become a part of daily work.…”