Real-time estimation of BER & SNR in optical communication channels (Invited Paper)

In optical communications the transportable bandwidth has exceeded Tbps per fiber, as a result of a dense grid of optical channels in the fiber, known as dense wavelength division multiplexing and which does not come without a price. Degradations and interactions due to non-linear and linear effects degrade the signal thus decreasing signal integrity and channel performance. Channel performance is greatly improved with error detecting and correcting codes that detect up to sixteen errors and correct up to eight within a block of information. However, estimation is limited to BER after monitoring many blocks, which takes valuable time particularly when the traffic per channel is huge. As a consequence, there is a need for fast estimation of the signal integrity and channel performance to ensure that the expected performance metrics are maintained. In this paper, we describe a statistical sampling methodology for the estimation of performance parameters such as BER, SNR, and Q-factor in a very short interval and for all-practical purposes in real-time.