MITSUBISHI

MITSUBISHI LASER DIODESML4XX16 SERIESFOR OPTICAL COMMUNICATION SYSTEMSI Far - field patternThe. ML4XX16 laser diodes lase in fundamentaltreanverse (TEoo) mode. and the mode does notchange with the current. They have a typicalemitting area (size of near-field pattern) of 2.1 x0.7 Il rn'. Fig.7 and Fig.8 show typical far- fieldradiation patterns in "parallel" and "perpendicular"planes.The full angles at half maximun points (FAHM)are typically 11 0 and 38 0 •Fig. 7 Far- field pattemsin plane parallel to heterojunction (J III) II1""--5mWII" r-3mWJ'I f'\t1mw~30 o 30Off- axis angle (deg.)Fig. 8 Far- field patternsin plane perpendicular to heterojunction (J J..'5a5oOff- axis angie (deg.)II Light output vs. monitoring output characteristicThe laser diodes emit beams from both of theirmirror surfaces. front and rear surfaces. The rearbeam can be used for monitoring power of frontbeam· since the rear beam is proportional to thefront one. Fig. 9 shows an example of light outputvs. monitoring photocurrent characteristics.When the front baeam output .is 3mW. 1mO.4mA typical and the monitor output currentincreases in proportion to the front beam output.isFig. 9 Light output vs. monitoring output current~,5540a. 3.;::>S::>0 2~~::; '"/LVVI1 LV0.2 0.4 0.6 0.8 1.0Monitoring output. Irn (rnA)2-68,... MITSUBISHI.... ELECTRIC