  Photonic methods of radio-frequency waveform generation and processing
provide performance and flexibility over electronic methods due to the
ultrawide bandwidth offered by the optical carriers. However, they suffer from
lack of integration and slow reconfiguration speed. Here we propose an
architecture of integrated photonic RF waveform generation and processing, and
implement it on a silicon chip fabricated in a semiconductor manufacturing
foundry. Our device can generate programmable RF bursts or continuous waveforms
with only the light source, electrical drives/controls and detectors being off
chip. It turns on and off an individual pulse in the RF burst within 4
nanoseconds, achieving a reconfiguration speed three orders of magnitude faster
than thermal tuning. The on-chip optical delay elements offers an integrated
approach to accurately manipulate individual RF waveform features without
constrains set by the speed and timing jitter of electronics, and should find
broad applications ranging from high-speed wireless to defense electronics.
