Mounting a FAC

[MechEng3]

Yeah! I love a good used micromanipulator...even if it is borrowed....just installed a FAC onto a 5 watter the first time! And no meds involved! OK I know it won't be pretty next time....OK celebration over. Back to work. Sorry no pics....too dang small for my cam....using 30X scope to work.....

[300EVIL]

LOL! Fun! 30 years from now we'll need electron microscopes to place FAC lenses.

[heruursciences]

It isn't too hard to mount a FAC, just tedious , and if you are not careful you can kill the LD. The best way by far is to make a micromanipulator that holds the fac lens in a short length of metal tubing mounted on an xyz stage.

The process is monitored with a video camera to monitor it when the laser is On, and a dissection scope modified with a 45 degree BBIR-HR beam splitter and target to get the FAC close enough to turn the laser ON. You will need a TEC cooling fixture for your LD, and run it pulsed at a very low duty cycle, just barely above threshold until you are almost perfect- equal divergence on the fast axis and slow axis- you'll get a rapidly diverging square beam.

When this is achived, place tiny drops of UV cure glue near the edge of the c-mount and cure with a blu-ray laser. finally either scribe and cleave the excess fac with a diamond scribe tool, or use a tightly focused 1-5w co2 laser to cut it.

It is best to practice on scrap/off-spec diodes till you get the hang of it as you will kill a few of them unless very lucky.

[300EVIL]

Yeah, piece of cake!

[heruursciences]

Yeah not exactly a piece of cake, but once you have the equipment set up then the actual mounting is not all that much harder than soldering tiny SMD parts by hand. The hard part is the positioning, the easy part is the mounting itself.

[MechEng3]

No practice needed...done many times before.....just happy this one went so well and so fast. I have done it before without the aid of any fancy positioning tools....and have had very good results. Now with the lasers I am servicing...the precision and beam quality has to be better than good or it works. Tools do make life good......and I cut the FAC before the install....my tooling is set up to do the job with CCD cams and small cabinet to keep things clean...recirculation, filtered atmosphere. 473's don't like dust on optics. I have seen them come to me with melted glass on what was left of the optics....beam shaping lenses. Now I have designed a different method that makes it so simple.....almost foolproof.