True time delays using conversion/dispersion with flat magnitude response for wideband analog RF signals

Abstract

We demonstrate optical true time delays using wavelength conversion coupled with chromatic dispersion. The transfer function of the delay system is investigated, and it is shown that 3-dB bandwidth of the system can be increased over 40 GHz by using offset pumps. A flat magnitude response (<1 dB peak-peak, 0.2 dB RMS deviation) is achieved in the 1-30 GHz band. Calculated matched filter output to LFM pulses shows good performance, maintaining a > 30 dB peak-to-sidelobe-ratio. The effect of pump depletion during wavelength conversion is also investigated.