Abstract: The invention discloses a reflective micro-optic interferometric filter system, comprising a dual fiber collimator for expanding and outputting a beam, introduced from an input fiber, through a lens unit, collimating the beam through the lens unit, and outputting the collimated beam through an output fiber; an optical mirror for reflecting the expanded beam, outputted through the lens unit of the dual fiber collimator, and directing the reflected beam into the output fiber; and an optical plate positioned between the dual fiber collimator and the optical mirror, and having a refractive index modulation or a periodic pattern for inducing optical phase differences depending on the beam propagation path.