Fun with Fiber

But it ain't yet :-)

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So what are saying? You're making a cloud detector? LOL

Dang, Dropbox can be annoying.

Does this work?

Not exactly.

Say, how are those English lessons working out?

--

John Larkin Highland Technology Inc

Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom timing and laser controllers Photonics and fiberoptic TTL data links VME analog, thermocouple, LVDT, synchro, tachometer Multichannel arbitrary waveform generators

or possibly this...

Woiks. Did you burn that hole under the 4cm mark with the fiber output? Or was it the cat?

Brings up an interesting question: have you tried concentrating the sunlight at the input with a magnifier?

Gee John, how did you set up that outstanding optical bench so quickly?? Or was the signal injection end an odor bench?

-Tom

Negatory.

Best regards, Spehro Pefhany

OK, tried a handheld test with a lens, during a brief burst of sunlight. It got way, way brighter at the exit end.

My situation is that I have a vacuum chamber with stuff happening inside, and a window to observe through. I could stick a photodiode in the window and run coax back to my electronics, but I could run fiber, too, and avoid some EMI worries. I asked Phil and he did some math for me, and it looks like a large-core fiber will work, probably with no additional optics. My simplified math just considers the area of the window and the area of the fiber (ballpark 10,000 to 1 ratio) to figure how much of the available power will get into the fiber.

Looks like, on a cloudy day, an added lens won't help and might make things worse. But if the sun is distinct, a carefully aimed lens helps a lot. Presumably we'd use machined optical stuff, and not old velcro sneakers, in production.

I'd got used to assuming that you need a ball-lensed laser to get any amount of light into a fiber, but this 400u stuff is an optical fire hose.

I need to learn this stuff by Monday morning, at least enough to avoid saying anything really stupid.

Those are my gardening shoes, all natural and earthy. I don't do a lot of gardening, just the swing-a-pick grunt work now and then.

I tried a 50mm Rokkor lens from my camera set and aimed it at a white paper. That made the illumination onto the targeted paper spot substantially brighter. Ok, it's not cloudy up here but quite hazy, on account of all the smoke wafting around here from the American Fire and the Rim Fire.

That is one big fiber.

I need to learn MBA stuff until Monday morning. Plus layout guidance for a set of two boards which is expected to become ready for fab on Monday. But first I have to fire up the charcoal, we'll bake German-style farmer's bread in the trusty old Weber. Later it will be joined by ribs, brats and beer. From the time we kneaded it the dough for the bread has about tripled in diameter. Amazing.

Regarding those fire, our swamp cooler did an excellent job of keeping the air in the house nice and fresh while there was a permanent smoke stench outside. Until this morning, when there was a slight whiff in the house as if some circuitry in the lab had gone phut. Turned out the pads had become saturated with soot and there was a major soot pile in the basin, but nicely separated in the middle. So I cleaned it all out -> fresh air again. These things really rock.

Now it works.

Best regards, Spehro Pefhany

My usual supplier stocks 200/230 fiber (evidently an old industrial standard they still support) which I've considered grabbing a chunk of just for playing with. As unterminated fiber it's pretty cheap ($1.35/m simplex, 2.20 duplex, 3mm jacketed.)

If you try to do some illumination experiments, why not use some 1 mm (TOSLINK style) plastic fibers ?

A 70 W HID lamp and a few dozens of such fibers and you can make the star constellations into your ceiling :-).

Such constructions are also used in illuminating saunas, in which the ceiling temperature can easily exceed +120 C and/or 100 % RH. The HID lamp can be kept in a cool and dry environment, while the fibers carry the light to the hot and humid room.

I assume that these (and the 400 micron monster) are step index fibers, which may explain the ring images. Anyway, for image transmission (versus light transport), one needs graded-index fiber.

Joe Gwinn

Is it possible to transmit an image through any single fiber?