Abstract
Noise suppression in chaotic lidar with optical feedback (OF), optoelectronic feedback (OEF), and incoherent optical feedback (IOF) based on completed and generalized synchronization schemes under open- and close-loop are investigated numerically. Unlike the previously proposed chaotic lidar that directly correlates the received signal with the transmitted signal, using an additional receiver laser is proposed used to filter the environmental noise. Both white Gaussian noise in the amplitude and randomly fluctuate phase changing from − to are taken into account. The numerical results confirm that the chaotic lidar system utilizing a receiver laser for synchronization shows advantages of noise suppressions. In the OF system with low noise region, the direct correlation (conventional) scheme has better correlation performance than the completed synchronization scheme for SNR > 7 dB and the generalized synchronization scheme for SNR > 12 dB, respectively. When the noise increases to −23 dB < SNR < 12 dB, a suitable optical coupling strength (OF,c = 0.3) must be chosen in the OF synchronization scheme under the generalized synchronization condition to achieve high correlation coefficient, while a insignificant noise suppression in the completed synchronization condition is presented. Compared with the OF system, high correlation performances close to 1 in the OEF system are shown for both the conventional scheme and the synchronization scheme in low noise region (SNR > 7dB). When the noise increases to −23 dB < SNR < −1 dB under the completed synchronization condition and −23 dB < SNR < 10 dB under the generalized synchronization condition, a good noise suppression performance is observed. In the IOF system, on the other hand, synchronization breaks easily in the large noise region. To sum up, the CLIDAR based on the OEF synchronization system has the best performance in noise suppression.