A　micro-scale　Fabry-Perot　interferometer　with　high　spectral　resolution　and　tunable　transmission　frequency　is　proposed.　In　this　scheme,　two　partially　reflecting　mirrors　with　a　separation　of　several　wavelengths　is　fabricated　in　a　waveguide,　and　a　two-level　emitter　is　located　between　the　mirrors　and　coupled　to　the　waveguide　with　chiral　interaction.　We　analytically　show　that　the　single　emitter　plays　the　role　of　a　strongly　dispersive　medium　and　the　full　width　at　half　maximum　(FWHM)　of　the　transmission　fringes　around　the　resonance　frequency　of　the　emitter　can　be　narrowed　by　5　orders　of　magnitude.　The　proposed　micro-scale　interferometer　can　have　the　same　spectral　resolution　as　meter-scale　traditional　interferometers.　We　also　show　that　the　central　frequency　of　the　narrowed　transmission　fringe　can　be　tuned　by　adjusting　the　asymmetry　of　the　emitter-waveguide　coupling.　Our　scheme　has　potential　applications　in　the　fields　of　integrated　optical　circuit　and　quantum　information　processing.　(C)　2018　Elsevier　B.V.　All　rights　reserved.