Multiple-input single-output FIFO optical buffers with controllable fractional delay lines

Optical buffering is a major challenge in realizing all-optical packet switching. In this paper we propose a new buffer called a multiple-input single-output FIFO (MISO-FIFO) optical buffer that supports several functions normally associated with electronic RAM. Our structure reduces the physical size of a buffer by up to an order of magnitude or more by allowing reuse of its basic optical delay line (ODL) elements. Moreover, by using controllable fractional delay lines (CFDLs) as the basic building block we are able to reduce the size and frequency of voids in the output of the buffer. We develop a Markov Chain (MC) model for the performance of our new buffering scheme, and demonstrate the advantages of our structure over buffer structures that use ODLs in terms of throughput and link utilization. (C) 2008 Optical Society of America