Publication
We show that the spectral broadening of the pump pulse through self-phase modulation in a time-domain distributed Brillouin sensor has a considerably detrimental effect in the measurement, especially in the case of long distances and high-resolution pulses. Using 30ns pump pulses with peak power of 276mW, self-phase modulation leads to a doubling of the effective gain linewidth after some 20km, which is equivalent to a contrast loss of 2dB in the measurement. The impact is higher for shorter pulses (higher resolution). The theoretical modeling is fully confirmed by experimental results.
Tobias Kippenberg, Junqiu Liu, Wenle Weng, Tobias Herr, Miles Henry Anderson