Analysis of wavelength sensitivity of coupling coefficients and inter-core crosstalk in a 9 core fiber

Wavelength dependence of coupling coefficient and inter-core crosstalk in a homogeneous 9-core Multi-core Optical Fiber (MCF) are investigated analytically. The analysis is further extended to evaluate the mean crosstalk power at the output of any core with light launched into the center core of the MCF. Analysis shows that the mean crosstalk power increases with the increase in operating wavelength. Propagation length dependence of crosstalk power is also investigated using Coupled Power Theory. It is noticed that the crosstalk increases exponentially with the increase in propagation length (z), and it is higher with the higher coupling coefficient at a particular propagation distance. The crosstalk is also not periodic with the propagation distance, z. The behavior of relative crosstalk power with respect to the operating wavelength within a span of C and L band (1530-1620 nm) is also investigated analytically. It is noticed that the relative crosstalk increases almost linearly with core pitch as well as with operating wavelength. It is also seen that the relative crosstalk power (in dB) is more in the MCF with less number of cores when it is varied with respect to wavelength. From the analysis, it appears that the inter-core coupling induced crosstalk increases with respect to the operating wavelength even when the core density is reduced.