Abstract

The function of ‘memory’ is one of the key building blocks to implement advanced information processing in future ultrahigh-speed photonic networks. For example, memory allows 100Gbit/s optical packets [1] to be buffered and queued for subsequent processing of the data and memory is also an intrinsic function for serial optical computing systems [2]. Several types of optical memory have already been demonstrated using recirculating fibre loops. These memories are either pulse-preserving, where the same optical pulses propagate on each circulation of the storage loop [3,4], or regenerative where the pulses are replaced after some number of memory circulations [5,6,7,8]. For pulse-preservation memories, the long term stability of the data pattern depends on being able to retime and reshape the optical pulses within the memory loop, since it acts like a long transmission line [3,4,9]. In all configurations, the longest achieved stable storage time was of the order of ten minutes. Here we describe a novel all-optical regenerative memory where an optical pulse binary data pattern can be stored for several hours. The highly stable operation is achieved by fully regenerating the data pattern after each circulation of an optical fibre delay line. This all-optical architecture is a combination of two nonlinear optical switching elements (TOAD/SLALOM [10,11]) which have low switching energies (≈ 1 pJ) and can in principle operate at bit-rates approaching 100Gbits^-1 [12].

© 1997 Optical Society of America