  We use an effective one-dimensional Gross-Pitaevskii equation to study bright
matter-wave solitons held in a tightly confining toroidal trapping potential,
in a rotating frame of reference, as they are split and recombined on narrow
barrier potentials. In particular, we present an analytical and numerical
analysis of the phase evolution of the solitons and delimit a velocity regime
in which soliton Sagnac interferometry is possible, taking account of the
effect of quantum uncertainty.
