  Sensitivity of gravitational-wave detectors is limited in the high-frequency
band by quantum shot noise and eventually limited by the optical loss in signal
recycling cavity. This limit is the main obstacle on the way to detect
gravitational waves from the binary neutron star mergers in the current and the
future generation detectors, as it does not depend on either the arm length, or
the injected squeezing level. In this paper, we come up with the sloshing
Sagnac interferometer topology, which can be obtained from the Michelson
interferometer by optically connecting the end mirrors into an additional
optical cavity. This transforms the interferometer into a triply-coupled cavity
system capable of beating the loss-induced high-frequency limit of the
signal-recycled Michelson interferometer. With advanced LIGO+ comparable
parameters, a sloshing-Sagnac scheme can achieve 7 times better sensitivity at
2.5\,kHz or 4 times better signal to noise ratio for a typical waveform of
binary neutron post merge. Being an evolution of Michelson interferometer, the
sloshing-Sagnac interferometer can possibly be used as a topology for the
future generation detectors and upgrade of current detectors.
