  We have studied the tunneling conductance in two dimensional electron gas /
insulator / superconductor junctions in the presence of Rashba spin-orbit
coupling (RSOC). It is found that for low insulating barrier the tunneling
conductance is suppressed by the RSOC while for high insulating barrier it is
almost independent of the RSOC. We also find the reentrant behavior of the
conductance at zero voltage as a function of RSOC for intermediate insulating
barrier strength. The results are essentially different from those predicted in
ferromagnet / superconductor junctions. The present derivation of the
conductance is applicable to arbitrary velocity operator with off-diagonal
components.
