A widely tunable high precision chaotic fiber laser is proposed and experimentally demonstrated.A tunable fiber Bragg grating(TFBG) filter is used as a tuning element to determine the turning range from 1533 nm to 1558 nm with a linewidth of 0.5 nm at any wavelength.The wide tuning range is capable of supporting 32 wavelength-division multiplexing(WDM) channels with 100 GHz channel spacing.All single wavelengths are found to be chaotic with 10 GHz bandwidth.The full width at half maximum(FWHM) of the chaotic correlation curve of the different wavelengths is on a picosecond time scale,thereby offering millimeter spatial resolution in WDM detection.
We experimentally demonstrate the chaotic generation in a figure-of-eight erbium-doped fiber laser (F8L) with an optical fiber ring (OFR). With an appropriate combination of polarization controllers, we find that the fiber laser exhibits period-doubling route to chaos, and the chaotic self-synchronous dynamics has a tendency to be reduced significantly. The experimental results show the tendency is related to the interference and the nonlinear phase shift of light in the optical fiber ring. Meanwhile, the chaotic dynamics is related to the polarization state and pump power.
Chaotic laser radar based on correlation detection is a high-resolution measurement tool for remotely mon- itoring targets or objects. However, its effective range is often limited by the side-lobe noise of correlation trace, which is always increased by the randomness of the chaotic signal itself and other transmission channel noises or interferences. The experimental result indicates that the wavelet denoising method can recover the real chaotic lidar signal in strong period noise disturbance, and a signal-to-noise ratio of about 8 dB is increased. Moreover, the correlation average discrete-component elimination algorithm significantly suppresses the side-lobe noise of the correlation trace when 20 dB of chaotic noise is embedded into the chaotic probe signal. Both methods have advantages and disadvantages.
