Saroj Saini , Ashok Kumar IJSRE Volume 4 Issue 4 April 2016 Page 5269 Volume||4||Issue||04||April-2016||Pages-5269-5274||ISSN(e):2321-7545 Website: http://ijsae.in DOI: http://dx.doi.org/10.18535/ijsre/v4i04.26 Fault Tolerance in Passive Optical Networks: A Survey Authors Saroj Saini 1 , Ashok Kumar 2 1 Department of Electronics and communication Engineering Ambala college of Engineering Applied Research Ambala, INDIA 2 Department of Electronics and communication Engineering Ambala College of Engineering Applied Research Ambala, INDIA Email- swtsanju98@gmail.com, ashokcalicut 1993@gmail.com ABSTRACT Passive optical networks play an important role in fiber access system in the world today. Time division multiplexing-passive optical network is a fast emerging architecture that uses only passive components. In wavelength division multiplexing, passive optical network each light path can carry a huge amount of traffic failure may damage the end user applications. Hence fault tolerance has an important issue on this network. In a survey Studies many architectures, protocols and techniques to remove or overcome failures in the access network. Also in this survey study, methods for recovering from channel failures, link failures and node failures. In this paper we discussed the performance of the survey. Survivability is a critical issue in a wavelength division multiplexing optical networks. Keywords- PON, WDM, Fault Tolerance I. INTRODUCTION With the integration of Electronic and Communication technologies and the optical fiber communication techniques, Telecommunication networks are gives the fastest and high quality services to the users. Optical and Wireless networks are initially developed for many or different communication scenarios. Optical networks are mainly used for high bandwidth and long distance communication [1]. Optical fiber, becomes the dominated transport medium in the telecommunication systems because of its advantages in scalability, capacity, cost and reliability. Now a day’s optical fiber is the backbone of the networks [2]. Passive Optical Networks (PON) In telecommunication networks passive optical networks plays an important role in that time. In which passive components are used. Because of its important they gained more attention in the industry world. It is developed by a single fiber, in which unpowered splitters are used to transmit signal to multiple end points. PON includes of a optical line terminal (OLT), optical network units (ONUs) and optical network terminals (ONTs)at the end point. It is a form of fiber optic access network. For Time Division Multiplexing Passive Optical Network(TDM-PON), a passive splitter is used in the optical distribution network (ODN). Each ONUs and ONTs are bust multiplexed in the time domain [3]. Wavelength Division Multiplexing (WDM) WDM is the backbone of passive optical networks. The next generation transport networks called intelligent optical network that is a wavelength division multiplexing networks. They are based on passive optical components [4]. Definition,(Transmit the data in multiple streams, with the help of exclusive properties of fiber optics). In WDM , light path carry a huge amount of data, also they provided the capability to transfer