Maged Esmail

Abstract In order to enable new services that require high data rates over longer distances, the optical fiber substitutes the copper cable step by step in the access network area. Time division multiplexed Passive optical network (TDM-PON) is a fast emerging architecture that uses passive components only between the customer and the central office. PON operators need a monitoring system for the physical layer to guarantee high service quality.

In order to enable new services that require high data rates over longer distances, the optical fiber substitutes the copper cable step by step in the access network area. Time division multiplexed - Passive optical network (TDM-PON) is a fast emerging architecture that uses only passive components between the customer and the central office. PON operators need a monitoring system for the physical layer to guarantee high service quality. This monitoring system is necessary during the fiber installation, final network installation testing, regular operation of the network, and for fault localization. First, in this paper, we present the motivations, requirements and challenges of TDM-PON monitoring. Second, we make an exhaustive review of the monitoring techniques and systems for TDM-PON, mostly proposed within the last five years. In our survey we include the approaches already available in the market even with limited performance and those still in research. Third, we make a detailed classification of all these approaches and qualitatively compare characteristics in a list of performance parameters and aspects. Finally, we outline open issues and future research perspectives in physical layer PON monitoring that may target higher performance, lower cost, or scalability to next generation PON architectures. This includes wavelength division multiplexing (WDM), TDM over WDM or long-reach PONs intended to extend the reach from 20 up to 100 km distances and beyond.

In this paper, a network fault management and protection system for the ring-and-spur long-reach passive optical network (LR-PON) is proposed. We exploit an adapted, enhanced performance, and inexpensive passive optical components in the field and electronic switches in the central office (CO). Our system allows detecting and localizing not only faulty segments but also faulty nodes, hence alleviating the false alarm probability encountered in previous systems. We show that using ring duplication protection in LR-PON can save half the cost compared to full duplication protection with relatively high reliability performance (99.972%). We describe the implementation strategy of our system in several well known metro network topologies including: (1) single ring, (2) double ring and (3) double fiber pair based ring. The architecture of the remote nodes and the central office is described in addition to the appropriate placement of the passive monitoring devices. We derive an expression for the upper bound notification and recovery times. Moreover, we found that our system can recover from a fault in about 0.5ms as an upper bound.

In this paper we propose a novel simple periodic optical encoder for centralized fault monitoring of fiber-to-the-X (FTTX) passive optical networks (PONs). This optical encoder exploits a fiber ring with a different length for each distribution/drop fiber to produce a different periodic code. This reduces the cost of monitoring system while maintains good performance and high capacity. We investigate the design issues of this coding based monitoring system and evaluate its performance in terms of signal to noise ratio (SNR), probability of false alarm (PFA) and probability of misdetection (PMD). We obtain an SNR of 12.5dB for a 32 customers network in one shot measurement. By repeating the measurement multiple times we achieve a capacity of 64 to 256 in expense of longer measurement time. Moreover, the system accomplishes a PMD ≈ 2 *10-9 for a PFA= 10-6 in a 64 customers network in 4ms.

This paper proposes a novel periodic optical encoder forcentralized fault monitoring of fiber-to-the home (FTTH)passive optical networks (PONs). The encoder exploits afiber ring to produce a periodic code. This reduces thecost of monitoring system while maintains goodperformance and high capacity. We evaluate theperformance of this encoding system in terms of signal tonoise ratio (SNR). We obtain an SNR of 12.5 dB for a 32customers network in one shot measurement. We alsoshow that capacity of 64, 128 and 256 could beaccommodated in expense of larger but acceptablemeasurement time.