Wideband delays generated in an all-optical tunable delay line, preserving signal wavelength and bandwidth

A novel technique to produce large all-optically controlled tunable delays of 100 ps pulse train in optical fibers is demonstrated. The configuration of the delay line basically consists of two main stages: the wavelength conversion via semiconductor optical amplifiers and the group velocity delaying via a dispersive optical medium. The wavelength-converted signal was precisely delayed over a wide temporal range from picoseconds to nanoseconds using a dispersive fiber, preserving the wavelength and the bandwidth of the signal. 100 ps FWHM signal pulses were delayed continuously up to 14 ns with moderate pulse distortion, corresponding to a 140-bit delay.