All-optical tunable delay-line memory based on a semiconductor cavity-soliton laser

Cavity soliton lasers in a vertical-cavity surface-emitting laser with a saturable absorber can spontaneously move provided that a proper ratio of the carrier lifetimes in the amplifier and in the absorber is considered. Use is made of this fact to propose a scheme based on which a tunable all-optical delay line can be demonstrated. This easy-to-realize delay device exhibits high delay range, a very good delay resolution, and a wide extent of available data bandwidth. Also it is shown that the ratio of delay time to pulse duration (fractional delay) can be as large as 2300.