Influence of Optical Fiber Length on the Jitter Performance of Subsampled Photonic Downconverter for S-band RADAR Systems

A packaged sub-sampled photonic downconverter is demonstrated with digitization bandwidth of 42.3 MHz for S-band operation. Nyquist folding of a single-tone signal at 2.517 GHz has been demonstrated successfully. Further, impact of length of fiber spool in front of optical-to-electrical converter i.e. photodiode has been studied for various RF input power levels ranging from 2 km to 10 km in terms of phase noise and timing jitter of sub-sampled signal.