MITSUBISHI

MITSUBISHI LASER DIODESML4XX5 SERIESFOR OPTICAL INFORMATION SYSTEMSSAMPLE CHARACTERISTICSI Llgth output va. forward currentTypical light output vs. forward currentcharacteristics are shown in Fig.l. The thresholdcurrent for lasingis typically 35mA at roomtemperature. Above the threshold, the light outputincreases linearly with current, and no kinks areobserved in the curves. An optical power of about3mW is obtained at Ith + 10mA.Because Ith and slope efficiency 7J(dPo/ dlF) istemperature dependent, obtaining a constant outputat varying temperatures requires to control the casetemperature Tc or the laser current. (Control thecase temperature or laser current such that theoutput current of the built-in monitor PO becomesconstant.).E.2'..JFig. 1 Light output VS. forward current5421/'/1/!~~~/F50Y;j)10 20 30 40 50 60Forward current IF (mA)II Temperature dependence of threshold current(lth}A typical temperature dependence of the thresholdcurrent is shown in Fig. 2. The characteristictemperature To of the threshold current is typically130K in Tc;:;; 50·C, where the definition of To is Ithoc exp (T c/T 0)Fig. 2 Temperature dependence of threshold current:(§EEi!!:;u'" '0.t:.