Based　on　the　analysis　of　Talbot　phase-locking　theory　of　edge　emitting　semiconductor　lasers,　a　method　to　obtain　a　single　in-phase　mode　on　a　tapered　laser　chip　is　proposed.　A　phase-locked　model　with　1/2　Talbot　spatial　filter　cavity　for　mode　selection　placed　between　8　emitters　on　each　facet　is　set　up.　Based　on　the　mode　coupling　rate　equation　theory,　the　parallel　coupling　phase-locking　conditions　with　different　fill　factors　is　analyzed.　The　results　show　that　the　stable　parallel　coupling　phase　lock　can　be　achieved　for　8　emitters　with　the　pitch　of　20　um,　when　the　fill　factor　is　set　between　0.06　and　0.12,　and　the　phase-locking　time　is　about　3　ns.　The　supermode　threshold　gains　are　also　calculated　under　different　fill　factors.　In　the　phase-locked　model,　when　the　fill　factor　is　approximately　0.1,　the　threshold　gain　difference　between　the　in-phase　mode　and　out-phase　mode　could　reach　the　maximum,　which　is　around　78cm(-1).　Therefore,　single　in-phase　mode　output　of　this　novel　laser　with　Talbot　cavity　becomes　more　robust.　The　simulation　analysis　provides　a　reliable　theoretical　support　for　the　preparation　of　a　coherent　array　laser　with　a　single　in-phase　mode　output.