Photonic Synthesis of Spread Spectrum Radio Frequency Waveforms With Arbitrarily Long Time Apertures

A photonic technique is proposed to generate spread spectrum radio frequency waveforms with both high RF bandwidth and arbitrarily long temporal period. By switching the polarity of full duty cycle chirped waveforms according to a pseudorandom sequence, we can increase the waveform repetition period under electronic control while preserving RF bandwidth and average power. Proof-of-principle ranging experiments are presented to demonstrate the improvement our technique provides with respect to range ambiguity.