This　article　assembles　a　distributed　feedback　(DFB)　cavity　on　the　sidewalls　of　the　optical　fiber　by　using　very　simple　fabrication　techniques　including　two-beam　interference　lithography　and　dip-coating.　The　DFB　laser　structure　comprises　graduated　gratings　on　the　optical　fiber　sidewalls　which　are　covered　with　a　layer　of　colloidal　quantum　dots.　Directional　DFB　lasing　is　observed　from　the　fiber　facet　due　to　the　coupling　effect　between　the　grating　and　the　optical　fiber.　The　directional　lasing　from　the　optical　fiber　facet　exhibits　a　small　solid　divergence　angle　as　compared　to　the　conventional　laser.　It　can　be　attributed　to　the　two-dimensional　light　confinement　in　the　fiber　waveguide.　An　analytical　approach　based　on　the　Bragg　condition　and　the　coupled-wave　theory　was　developed　to　explain　the　characteristics　of　the　laser　device.　The　intensity　of　the　output　coupled　laser　is　tuned　by　the　coupling　coefficient,　which　is　determined　by　the　angle　between　the　grating　vector　and　the　fiber　axis.　These　results　afford　opportunities　to　integrate　different　DFB　lasers　on　the　same　optical　fiber　sidewall,　achieving　multi-wavelength　self-aligned　DFB　lasers　for　a　directional　emission.　The　proposed　technique　may　provide　an　alternative　to　integrating　DFB　lasers　for　applications　in　networking,　optical　sensing,　and　power　delivery.