Specifications
2.2 Current 7
2.2 Current
The outputof semiconductorlaserdiodesfollowa nominallylinear
powervs. currentrelationship,oncethecurrentisaboveadevice-
specificthreshold (seeFig.2.1). Initially thecurrentshouldbeset
above threshold, but well below the nominal maximum operating
current, until the laser is fully aligned.
0
20
40
60
80
100
120
140
0 20 40 60 80 100 120 140 160 180 200
Power (mW)
Injecon current (mA)
Bare 150mW diode
780.243nm
Extracavity
esmate
Figure 2.1: Sample laserdiodepower-current characteristic curves,with
andwithoutanexternalcavity. Theoutputforadiodewithgoodanti-
reflectioncoatingisnegligible. Thestepsshowthatforhighercurrents,
someof thelightfromthe diodeisnottransmitted bythefilter,typically
becausetheexternalcavitymodefrequencyisnotperfectlyalignedwith
the filter transmission frequency.