Steady-state accumulated complex spectral gratings for correlation signal processing

Summary form only given. Complex spectral gratings, accumulated to nearly steady-state in a short-term persistent inhomogeneously broadened optical transition, have been demonstrated by repeated application of a pair of frequency stabilized and low power-optical pulses (i.e. continuous programming). Provided the grating is not saturated, it can perform continuous correlation of an amplitude and/or phase modulated optical waveform at multi-gigahertz rates with large time-bandwidth products. The present work demonstrates continuous programming of a complex spectral grating, representing a 30-bit pattern and 4 microsecond time delay, to and beyond steady state. Grating accumulation and maintenance is observed by applying a probe pulse (identical to the pattern) after each programming pulse pair. Each probe stimulates an optical coherent transient emitted signal that represents the correlation of the pattern and probe. The probe was non-destructive to the grating, and consequently did not interfere with programming. The frequency reference was a transient, regenerating spectral hole created by the optical carrier in the same inhomogeneously broadened transition.