Reserch On Testing Of VCSEL's Optical Output Characteristic

As a new kind of semiconductor laser,vertical-cavity surface-emitting lasers(VCSEL) havesuch merits as low threshold,woking in single longitudinal mode,small angle of divergence,highdynamic modulating frequency,easily implemented two-dimension integration than conventionaledge emitting lasers.VCSEL have an significant implication prospect in opticalcommunication,optical interconnection,image signal processing,etc.With it's increasingapplication,the research of VCSEL's optical output characteristic becomes very important.Butthese instruments for the research are all much expensive,which are unfavorable for thepopularization in common labs.This dissertation studied the testing of VCSEL's optical outputcharacteristic.We put forward a scheme and designed a system for the tesitng of VCSEL's opticaloutput characteristic,which can be stored into the computer instead of the conventional recordinginstrument,which can result in large numbers of drawing sheets.This system have a certain extentvalue in use because of it's convenient utilization and low cost.This dissertation introduced the scheme of testing system of optical output characteristic ofVCSEL.We designed a stable current supply of saw-tooth wave with SCM,the cycle and peakvalue of which can adjusted. We also designed a subtraction circuit ,from which we could get thevoltage of VCSEL ,and a circuit of photoelectric detection,the voltage of resistance in whichcould reflect the change of VCSEL's light power.We sent the two signals above to image displayand data transmitting system,so we can get the two testing curves, V-I curve and P-I curve,whichcan be stored into the computer.We made a test of the VCSEL with the system we designed above and got a series of curveswhich were sent to computer for storage. At last ,we put forward a scheme of improvement forthe precision of testing results and stability of the system.