  We implement two types of matter-wave interferometers using trapped
Bose-condensed Feshbach molecules, from weak to strong interactions. In each
case, we focus on investigating interaction effects and their implications for
the performance. In the Ramsey-type interferometer where interference between
the two motional quantum states in an optical lattice is observed,
interparticle interactions are found to induce energy shifts in the states.
Consequently, this results in a reduction of the interferometer frequency and
introduces a phase shift during the lattice pulses used for state manipulation.
Furthermore, nonuniformity leads to dephasing and collisional effects
contribute to the degradation of contrast. In the Michelson-type
interferometer, where matter waves are spatially split and recombined in a
waveguide, interference is observed in the presence of significant interaction,
however coherence degrades with increasing interaction strength. Notably,
coherence is also observed in thermal clouds, indicating the white-light nature
of the implemented Michelson-type interferometer.
