Cw Raman lasing characteristics of highly nonlinear photonic crystal fibers (PCF) are numerically investigated. The numerical approach is based on a pseudospectral algorithm developed earlier. Different pumping (forward, backward, and bidirectional) configurations are numerically simulated and the resultant efficiencies are shown to be the same under similar conditions. It is shown that the differences arise due to the pump being either single- or double-pass. (c) 2012 Elsevier GmbH. All rights reserved.