MITSUBISHI

MITSUBISHI LASER DIODESML4XX14 SERIESFOR OPTICAL INFORMATION SYSTEMSSAMPLE CHARACTERISTICSD Light output vs. forward currentTypical light output vs. forward current characteristicsare shown in Fig.l. The threshold currentfor lasing is typically 30mA at room temperature.Above the threshold, the light output increaseslinearly with current, and no kinks are observed inthe curves. An optical power of about 3mW isobtained at Ith + 12 rnA.Beacause Ith and slope efficiency 7J (dPo/ dlF) istemperature dependent, obtaining a constant outputat varying tern - peratures requires to control thecase temperature Tc or the laser current. (Controlthe case temperature or laser current such that theoutput current of the built-in monitor PO becomesconstant.)Fig. 1 Light output VS. forward current5~--~-----'--~~-r--~Forward current. IF (mA)a Temperature dependence of threshold current (lth)A typical temperature dependence of the thresholdcurrent is shown in Fig. 2. The characteristictempera'ture To of the threshold current is typically150K in Tc ~ 60°C, where the definition of To is Ithex: exp (Tc/To).Fig. 2 Temperature dependence of threshold current":20.t:'" ~.t:f-7050---40-I-- r---3020102030 40 50 60 70Case temperature. Tc ('C)I Temperature dependence of slope efficiencyA typical temperature dependence of the slopeefficiency 7J is shown in Fig.3. The gradient is- O.0003mW/mA/"C.Fig. 3 Temperature dependence of slope efficiency