In order to solve the facet catastrophic optical damage (COD) which is caused by the facet heating due to optical absorption in the mirror region,t he effect of intermixing on InGaAs/AlGaAs quantum well structure using impurity-free vacancy disordering (IFVD) technique is investigated.The SiO_2dielectric films are grown on the structure of AlGaAs/InGaAs -MQW/GaAs-buffer layer/InGaAs by plasma enhanced chemical vapor deposition (PECVD).Then,quantum well intermixing (QWI) is realized by the impurity-free vacancy diffusion (IFVD ) technology after rapid thermal annealing (RTA) at N_2atmosphere.Through the experiment we find that the magnitude of the blue shift changes with the anneal ing time and the thickness of the dielectric layer.The thicker dielectric layer under the same annealing temperature and the longer annealing time,the larger blue shi ft we get.However,when the annealing time is relatively long in high annealing temperature,the greater damage is made to quantum well from annealing.Cycle-ann ealing in high temperature for short time is selected to ensure that quantum wells can intermix evidently under the condition of no obvious damage.46nm blue shift is achieved by applying a cycle-annealing at 850℃ in 6min for 5cycles and t he PL peak keeps more than 80% of that of the as-grown sample.