  Space division multiplexing using multi-core fiber (MCF) is a promising
solution to cope with the capacity crunch in standard single-mode fiber based
optical communication systems. Nevertheless, the achievable capacity of MCF is
limited by inter-core crosstalk (IC-XT). Many existing researches treat IC-XT
as a static interference, however, recent research shows that IC-XT varies with
time, wavelength and baud rate. This inherent stochastic feature requires a
comprehensive characterization of the behaviour of MCF to its application in
practical transmission systems and the theoretical understanding of IC-XT
phenomenon. In this paper, we experimentally investigate the IC-XT behaviour of
an 8-core trench-assisted MCF in a temperature-controlled environment, using
popular modulation formats. We compare the measured results with the
theoretical prediction to validate the analytical IC-XT models previously
developed. Moreover, we explore the effects of the measurement configurations
on the IC-XT accuracy and present an analysis on the IC-XT step distribution.
Our results indicate that a number of transmission parameters have significant
influence on the strength and volatility of IC-XT. Moreover, the averaging time
of the power meter and the observation time window can affect the value of the
observed IC-XT, the degrees of the effects vary with the type of the source
signals.
