  We propose a semiconductor structure that can rotate the electron spin
without using ferromagnetic contacts, tunneling barriers, external radiation
etc. The structure consists of a strongly curved one-dimensional ballistic wire
with intrinsic spin-orbit interactions of Rashba type. Our calculations and
analytical formulae show that the proposed device can redistribute the current
densities between the two spin-split modes without backscattering and, thus,
serve as a reflectionless and high-speed spin switcher. Using parameters
relevant for InAs we investigate the projection of current density spin
polarization on the spin-quantization axis as a function of the Rashba
constant, external magnetic field, and radius of the wire's curvature.
