MITSUBISHI

MITSUBISHI LASER DIODESML8XX1 SERIESFOR OPTICAL COMMUNICATIONSAMPLE CHARACTERISTICSI LIght output vs. forward currentTypical I.ight output vs. forward currentcharacteristics are shown in Fig. 1. The thresholdcurrent for lasing is typically 15mA at roomtemperature. Above the threshold, the light outputincreases linearly with current, and no kinks areobserved in ~he5mW is obtained at Ith + 15mA.curves. An optical power of aboutAs can be seen in Fig.1 Ith and slope efficiencyTJ (dPo / dlF) depends on case temperature,obtaining a constant output at varyingtemperatures 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.)Fa Temperature dependence of threshold current (lth),operating current (lop) and slope efficiency ( TJ )A typical temperature dependence of the thresholdcurrent and operating current is shown in Fig. 2.The characteristic temperature To of the thresholdcurrent is typically 45K in Tc;:;;40·C, 35K in. Tc>40·C,where the definition of To is Ith 0: exp (Tc/To).~-500..:;0.:;0E.!1'-'Fig. 1 Light output vs. forward current6r----n~'"--~r----r---,432