Abstract: This paper Burst mode synchronization is a key techno logy in passive optical network that utilizes time division multi access (TDMA) with single mode fiber. For the clock recovery in burst mode transmission, a burst mode synchronizer using keyword detection based on multiphase clock is usually used. In this article, based on research in asynchronous transfer moder-passive optical network, author described a method to design burst synchronizer in AS1773 protocol. This synchronizer is implemented by field programmable gate array, which can achieve high performance with low cost, short developing period.