Dual-wavelength ranging system and method for improving measurement dynamic range

The invention relates to a dual-wavelength ranging system and method for improving a measurement dynamic range, and the method comprises the steps: employing a polarized light output subsystem comprising two lasers with different wavelengths as a continuous light emission source, and introducing radio frequency modulation signals with different frequencies through an electro-optical modulator; a half-wave plate and a beam combining end are used for aligning a fast axis and a slow axis in a polarization maintaining optical fiber to achieve dual-channel isolation of different wavelengths on polarization and frequency, the energy of probe light is improved through an optical fiber amplifier and output through an optical fiber coupler, and a Michelson interference system based on an optical fiber beam splitter is used for detecting the wavelength of the probe light. The length of the interference arm is changed through the electrically tunable delay line, the polarization beam splitter and the photoelectric detec