Fig. 1. Frequency response of laser echo signal

Fig. 2. The relationship between cutoff frequency and attenuation coefficient of seawater

Fig. 3. Time domain waveform of modulating pulse

Fig. 4. Dual frequency injection locking and frequency doubling system

Fig. 5. Time series, power spectrum, phase portrait and autocorrelation trace of chaotic laser output

Fig. 6. Chaos generated by two mode and three mode coupling in solid lasers

Fig. 7. The relation between the number of relevant calculation points and PNL

Fig. 8. Experimental device

Fig. 9. The ranging cross-correlation curve of clear water with turbidity of 0.55 NTU

Fig. 10. The ranging cross-correlation curve of clear water with turbidity of 6.77 NTU