As an emerging novel technology, optical buffering via fiber delay lines (FDLs) is adopted in optical burst switching (OBS) networks for contention resolution. In this paper, we study the blocking probability and the mean delay of an asynchronous single-wavelength optical buffer, where the burst arrival process is Poisson and burst-length distribution is general. With the aid of Level Crossing (LC) method, we first derive the integral equations to model the dynamics of the buffer. We then propose a method to solve these equations. Finally we present the mathematical expressions of blocking pro...