Photonic-assisted high-resolution incoherent back projection synthetic aperture radar imaging

We demonstrate the photonic-assisted high-resolution synthetic aperture radar imaging applying broadband photonic signal generation and a modified incoherent back projection (BP) imaging algorithm. The radar transmits linear frequency modulated (LFM) signals generated by period-one oscillation in an optically injected semiconductor laser. Since the signal bandwidth is greatly enlarged compared with traditional electric radars, a significantly improved imaging resolution can be achieved. Besides, we use a modified incoherent BP imaging algorithm with self-amplitude weighting and multiplicative tomography weighting, to further increase the imaging resolution and to suppress the undesired high-energy artifacts and background interferences. An experiment is carried out. Based on the established radar with a signal bandwidth as large as 12 GHz, high-resolution and clear images of different scenes are successfully constructed, through which the advantages of the proposed scheme over traditional BP imaging system can be soundly verified. The demonstrated scheme provides a good solution to enhance the performance of the incoherent BP imaging algorithm and simultaneously overcome the radar bandwidth limitation. It would find applications where high-resolution radar imaging is needed.