In　the　wet-oxidation　process,　we　used　a　new　home-made　infrared　light　source　microscope　and　a　CCD　observer　to　look　down　at　the　imaging　system　to　monitor　changes　in　the　color　of　oxidized　spots　on　the　wafer　being　oxidized.　According　to　this　ratio　which　was　calculated　by　comparing　the　size　of　the　oxidized　point　obtained　by　the　CCD　camera　with　the　actual　oxidation　point　size,　the　size　of　the　actual　oxidized　wafer　was　obtained　by　the　color　change　size　of　the　oxidized　point.　By　observing　the　color　change　size　of　the　oxidized　point,　the　oxidation　process　was　adjusted　to　ensure　the　accuracy　of　controlling　the　oxidation　aperture　of　vertical　cavity　surface　emitting　lasers(VCSELs)　to　within　±1　μm.　Based　on　the　oxidation　experiments,　the　effect　of　high　Al　content　on　the　shape　of　oxidation　pores,　the　change　of　oxidation　rate　with　temperature　and　the　change　of　oxidation　depth　with　time　were　obtained.　When　the　furnace　temperature　was　420,　the　temperature　of　the　water　bath　was　90　and　the　flow　rate　of　the　oxidizing　gas　was　200　mL/min,　the　oxidation　rate　was　0.31　μm/min　and　modulation　rate　of　the　850　nm　VCSELs　was　4×25　Gbit/s.　Room　temperature　conditions,　the　sub-unit　operating　voltage　2.2　V,　the　threshold　current　0.8　mA,　the　ramp　efficiency　of　0.8　W/A,　when　the　current　was　6　mA,　the　power　was　4.6　mW.　©　2018,　Science　Press.　All　right　reserved.