Simplex coded polarization optical time domain reflectometry system

In polarization optical time domain reflectometry (POTDR) system, the performance of polarimetric measurement is largely constrained by the low signal to noise ratio (SNR) due to the weak Rayleigh backscattering and the degradation of the degree of polarization (DOP) of signal light. It will be indispensable to improve the SNR without sacrificing the DOP of backscattered signal for a sufficient dynamic range. In this paper, a Simplex coded POTDR (sc-POTDR) system was proposed and demonstrated. The relationships between the signal's DOP and coding length/bit width were studied. Both numerical simulations and experiments show that the signal's DOP has nothing to do with the length of Simplex code and only reducing the bit width can suppress the temporal depolarization effect. Applying 511-bit Simplex codes, a coding gain of 10.125dB has been demonstrated.