4.3 Threshold optimisation 23
4. Removethebrassclampfromthecentralspindle,thenremovethe
threehexdrivescrewsholdingthecircularplateontopofthespindle
(see figure 4.2).
Figure 4.2: Removingtheintracavityfilterassembly. a)Threescrewsholdthe
top plate (pink)over the spindle.b) Spindle (green) must be alignedas pictured
before removal.
5. Rotatethefilterspindlesuchthatthefilteralignmentmark(themark
on the spindle, not the mark on the brass clamp) is aligned parallel
with the optical axis.
6. Gentlyprisethefilterassemblyfromthelaserbarrel(seefigure4.2).
If the filter seems stuck, it may be caught on the cateye output
couplerorlaserdiodetubesormayberotatedfromtherequired
orientation (see previous step).
7. Turnthe DLCon andadjustCURRENTto 5–10mAabovethethresh-
old specifiedin thelaser testreport.You shouldhave atleast 1mW
ofoutputpower,otherwiseincreasethecurrentfurther,butdonot
exceed the maximum safe current specified in the laser test report.
8. Monitor the laseroutput powerusing a powermeter asclose tothe
cateyeassemblyaspossible,thatis, beforetheisolator,withthe
powersensorangledslightlyfromorthogonaltotheopticalaxisto
protect the laser from back reflections from the sensor surface.
9. Adjust the cateye lens focus by rotating the threaded lens mount of
To Next Page
Loading...
Need help?
General
