  Highly coherent wave is favorable for applications in which phase retrieval
is necessary, yet a high coherent wave is prone to encounter Rayleigh fading
phenomenon as it passes through a medium of random scatters. As an exemplary
case, phase-sensitive optical time-domain reflectometry (\Phi-OTDR) utilizes
coherent interference of backscattering light along a fiber to achieve
ultra-sensitive acoustic sensing, but sensing locations with fading won't be
functional. Apart from the sensing domain, fading is also ubiquitous in optical
imaging and wireless telecommunication, therefore it is of great interest. In
this paper, we theoretically describe and experimentally verify how the fading
phenomena in one-dimension optical scatters will be suppressed with arbitrary
number of independent probing channels. We initially theoretically explained
why fading would cause severe noise in the demodulated phase of \Phi-OTDR; then
M-degree summation of incoherent scattered light-waves is studied for the
purpose of eliminating fading. Finally, the gain of the retrieved phase
signal-to-noise-ratio and its fluctuations were analytically derived and
experimentally verified. This work provides a guideline for fading elimination
in one-dimension optical scatters, and it also provides insight for optical
imaging and wireless telecommunication.
