Fig. 1. Schematic diagram of dual-frequency light differential phase based on static reference

Fig. 2. Schematic diagram of simulation for lower envelope multiplication of modulus values of dual-frequency components. (a) modulus value of low frequency component; (b) modulus value of high frequency component; (c) envelope of lower modulus value of low frequency component; (d) envelope of lower modulus value of high frequency component; (e) product of lower envelope

Fig. 3. Schematic diagram of phase optical time domain reflector based on isochronous time-division dual-frequency light

Fig. 4. Schematic diagram of Burst signal applied on PZT

Fig. 5. Schematic diagram of process of phase signal extraction in phase optical time domain reflector based on isochronous time-division dual-frequency light

Fig. 6. Initial processing of collected data. (a) Original coherent Rayleigh curve starting with 40 MHz frequency shift part; (b) original coherent Rayleigh curve starting with 80 MHz frequency shift part; (c) intermediate frequency filtered signal of 40 MHz frequency shift part; (d) intermediate frequency filtered signal of 80 MHz frequency shift part

Fig. 7. Modulus and statistical phase of collected data. (a) Modulus of 40 MHz frequency shift part; (b) modulus of 80 MHz frequency shift part; (c) statistical phase of 40 MHz frequency shift part; (d) statistical phase of 80 MHz frequency shift part

Fig. 8. Determination of reference position. (a) Modulus of two frequency components; (b) local plot of normalized distance sum; (c) local plot of product of normalized modulus minimums; (d) phase change

Fig. 9. Calculation of phase signal. (a) Localization presentation of Fig. 8 (d); (b) phase change after noise compensation for Fig. 9(a); (c) phase signal solved by the proposed method; (d) phase signal solved without reference position and reference phase