Splice loss calculations for index-guiding photonic crystal fibers

We have presented a detailed analysis of splice losses when an index-guiding photonic crystal fiber (PCF) is spliced to an identical PCF or to a step index single mode fiber (SMF). The calculations were based on the effective index model and on the Gaussian beam propagation theory. The wavelength dependence of the cladding index of the PCF has been taken properly into account. The effective spot size for different configurations of PCFs is obtained, which is used for computing the splice losses. The Gaussian approximation for the fundamental modal field leads to simple closed-form expressions for the splice losses produced by transverse, longitudinal and angular offsets.