AN MD80 DEVIATES SLIGHTLY FROM DEP COURSE AFTER ENCOUNTERING WAKE TURB PRODUCED BY ANOTHER MD80 DEPARTING THE SAME RWY AT DFW.

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I WAS THE PF. WE ASKED FOR A Z TXWY INTXN DEP ON RWY 18L AND WERE CLRED TO HOLD SHORT OF RWY 18L ON TXWY Z. ANOTHER MD80 DEPARTED FROM WF ON RWY 18L. SHORTLY AFTER HE PASSED US; TWR CLRED US FOR TAKEOFF FROM INTXN Z. I DELAYED APPLICATION OF TAKEOFF PWR UNTIL THE PRECEDING ACFT WAS DEFINITELY AIRBORNE. WE THEN EXECUTED THE TAKEOFF ROLL. DURING THE INITIAL CLB; WE ENCOUNTERED THE PRECEDING ACFT'S WAKE TURB. AT THAT TIME THE WINDS WERE OUT OF THE SSE; SO I DRIFTED SLIGHTLY TO THE L OF THE MAGENTA LINE TO GET OUT OF THE TURB WHICH SEEMED TO BE LOCATED RIGHT ON CTRLINE. DEP SOON ASKED US WHAT WE WERE DOING AND I REPLIED WE WERE ATTEMPTING TO AVOID THE WAKE TURB. AS FAR AS I COULD TELL; WE NEVER DEVIATED MORE THAN ONE DOT OFF THE COURSE DEVIATION INDICATOR ON THE PFD ON THE 10 MILE RANGE. WE WERE SUBSEQUENTLY CLRED DIRECT TO SLOTT; THEN TOLD TO PICK UP A HEADING TO GET PROPER TFC SEPARATION. EVENTUALLY WE WERE CLRED TO RESUME OUR OWN NAV. I BELIEVE THE PROB STARTED WHEN TWR CLRED US FOR TAKEOFF A BIT SOONER THAN HE SHOULD HAVE. I ALSO SUSPECT THE FACT WE WERE LIGHT WT (BETTER PERF) AND THAT WE TOOK OFF FROM AN INTXN AS OPPOSED TO FULL LENGTH (LIKE THE PREVIOUS ACFT) CONTRIBUTED TO US GETTING INTO THE WAKE TURB. HAD OUR TKOF CLRNC BEEN DELAYED A FEW MORE SECONDS; I DO BELIEVE THIS WHOLE EVENT COULD HAVE BEEN AVOIDED.