Coupling Laser beams into Fiber Optic Cable!

5:30 you can use focusing lense module from DVD drives which can give very focused beam but with extra electronically focusing features so With that fine tune would be much easier and you can note and tell by looking at input power of the coil to find exact focus Point .

Thanks for the collimator hacks! "Perfect" really is the enemy of "good enough" sometimes.

Great stuff, looking forward to the optical fibre sensing that comes next!

Superb video. Thanks for sharing this information.

We used to measure all sorts of stuff with fibers. I was working with Ion Implanters and fibers were used to cross the High Voltage barrier...cheers.

Very interesting, Les! Back in 1980, I attempted pushing a 5 watt argon beam down a 100 micron, single core quartz fiber, with a parabolic refractive index, which guided the beam towards the center. Didn't have any fancy lens assemblies, so I made mine with a piano-convex lens glued to the bottom of a glass tube, mounted vertically. The fiber end was held by a mechanical pencil's collet, which allowed for easy focusing. In order to eliminate surface reflections, I filled the glass tube with glycerol, which has ~ the same refractive index as the lens and fiber. The objective was to deliver a scanable beam to a pair of remote galvos, inside a scanning head, located in the lighting truss, in order to avoid heaving ion lasers on top of 10 towers. Worked fine.. until, as you explained, the beam missed the end of the fiber, heated the cladding, which expanded, making the alignment even worse. Furthermore, I was unable to achieve the appearance of a parallel beam for over 20 ft from 5 mm scanner mirrors. Laser Diodes have literally been game changers for laser entertainment. No 30 amp 3 phase, water cooling, hoses, pumps, frozen tubes during transport in winter. Higher wattage @ 10% the cost and hassle.

Great job sir thanks

Great video! Thanks for providing a simple way of doing something that can be frustrating and seem like shooting in the dark sometimes. I have a question though. Is there a preference between PC or APC couplers for better coupling performance?

The first time I collimated a single mode fiber coupled laser I was astonished at how good the beam get. This was with some of the 976nm 14 pin lasers. I want to fiber coupled a few visible diodes and see what the results are. I want to try putting the fiber right up against the die of the laser itself. Glad you posted this video, great work!

Good Stuff

love it

great video!!!

I liked the py spectrometer, so thank you for helping to guide us with a useful, affordable thermal imager. Just bought one from Amazon based on how well it works for you. PS, at least here in the USA its on sale.

I'm after some advice for a very specific problem. I need a laser powerful enough to burn carbon/soot but has a flexible fibre to get into hard places. The carbon/soot is located inside drilled holes within a car engine pistons. They are called the oil return holes and take oil from the oil control ring through the piston back into the crankcase, all car pistons have these holes, but some cars they get clogged up with carbon deposits. The idea is to remove the bottom oil pan and burn out this soot/carbon deposit with a laser, the holes are usually quite small maybe only 1/8 of an inch in diameter, but can be quite long all the way through the piston ( 1/2" or more at thickest part of the piston head). To clean out these holes requires engine rebuild, if its possible to clean them out with laser would be very advantageous.

£0.31 a metre in bulk, I never thought that kind of cable was so cheap.

Thanks Les, this was interesting again. I have used ball lenses for focusing light into/out fibres. They are mchanically a bit easier to handle and align

Excellent video! Not much of this kind of info on youtube. I'm currently researching how to optimally couple light from a 3mm diameter diffuse, incoherent source (back-illuminated skin) into a 500um fibre for a medical application (similar to pulse oximetry). Trying to get my head around the conservation of etendue concept to understand whether I can do better than just butting the fibre straight to the skin. Do you know whether collimation optics can help in this situation? Keep building!!

Genesis of lab-hacks playlist.

There was some ideas for mounting fibers for use with collimating lenses etc in the comments. For me I have had great success using a piece of aluminium about 30mm x 50mm x 2mm. I remove the buffer leaving the bare fibre exposed, make a clean cleave and then epoxy the fiber to the aluminium plate. Now it`s tempting to have the bar fiber hang over the edge a little, but this way its vulnerable to mechanical damage, so instead I cut or punch a small section of the edge away, maybe 5mm wide x 6mm deep. The fiber is mounted within this cutout so the end of the fiber is recessed from the edge of the strip but is still protruding over the edge of the recess. The assembly can then be bolted to supports on an optical bench or sled.

Awesome video, I'm tripping baaaalllzzz mayne. Jerry Garcia is GOD