Experimental demonstration of impulse-equivalent time-domain optical memory

We demonstrate the impulse-equivalent approach [Opt. Lett. 21, 833 (1996)] to time-domain storage of optical data. Using the 128-bit real Huffman–Ackroyd code as the write–read sequences, we have successfully stored a 42-μs-long stream containing 420 bits of data in a 40-MHz spectral channel in a Eu3+:Y2SiO5 crystal. The stored data were repeatedly recalled as many as eight times with high signal fidelity, showing no measurable sidelobe-induced noise. Data retrieval with the use of mismatched write–read pulses was also examined, and implications of the results for data encryption are discussed.