Guaranteeing the BER in transparent optical networks using OOK signaling

Abstract

Abstract-A network consisting of transparent optical nodes (TONs) can provide high speed end-to-end communication paths with very low bit-error rates (BERs). However, owing to component crosstalk and other degradations at TONs, the BER of a particular communication path traversing several TONs can be degraded by a few orders of magnitude even in the absence of component failure. Monitoring the quality-of-service (QoS) of a communication path has typically relied on sporadic BER testing and operation monitoring by the nodes using probe signals. Intermittent BER testing cannot provide continuous monitoring of the network QoS. On the other hand, the use of probe signals is not sensitive enough to detect the BER degradation. This work investigates a novel approach of monitoring service degradation at individual nodes using a wrap-around device which taps and compares signals from the input and the output at each TON along the lightpath. We propose a modification using hard limiters at TON inputs and derive the BER value that this modified method can guarantee in the presence of signal degradation due to coherent crosstalk at TONs.

Evaluation of coherence interference in optical wireless communication through multiscattering channels

“…j cos ͑ t ϩ j͒ , (11) where N s and N d are the number of single-and double-scattered waves reaching the detector at time t and i , j and i , j are their respective amplitudes and phase lags relative to the unscattered wave. We will assume that all single-scattered waves have the same amplitude s , which is the average value for all the single-scattered waves as described in Section 3.…”

“…8 -10 Furthermore, the quest for all-optical networks has also exposed the performance restrictions imposed by homodyne signal mixing at transparent optical nodes. 11 Preliminary work has been published examining single scattering in a fog of different optical densities (ODs) and for transmissions at different wavelengths. 12 In this work we pursue the subject further using two well-accepted fog models for the propagating channel medium and including double-scattered waves.…”