In this study, large-solid-core photonic crystal fibers with fixed air-hole diameter d=0.84 mu m and with fixed pitch length Lambda = 4.2 mu m are investigated for different d/Lambda ratios. The dispersions and the effective mode-areas are obtained and compared for both the structures. It is seen that the dispersion management is easier by using the fixed d structures, but for working around the same zero dispersion points in a large interval of d/Lambda the fixed A structures are more available. The A(eff) values larger than 100 mu m(2) are obtained with d/Lambda smaller than 0.2 for both the two structures. A(eff) increases rapidly with decreasing 0114 to 0.1 and then reaches to Aeff value of 500 mu m(2) at the d/Lambda = 0.1 for the fixed d structures. The single-mode regime for the two structures is also discussed. (C) 2011 Elsevier GmbH. All rights reserved.