Jacket for Plastic Optic Cable

My optics sucks..

I have some bare 1mm plastic optic cable..
You know..
Shine light in one end...see light at the other...

I have to put a jacket on the optic cable...
I plan on using wire insulation.. It's all I have handy..
I have black wire insulation but no white wire insulation..

Would I get more light transmission if I used white insulation?
The cable is 6ft long..

I think no matter what jacket I put on...Any high angle light will
bounce so much that it'll be eliminated by the reflective losses..
The dominant light that gets through is all from refraction.

Seems right..but I dunno for sure.
D from BC

 

No

 

Well...I guess that settles that..
D from BC

 

If it's a proper fiber, the jacket shouldn't make much difference at
all - the light is confined by reflecting off the inner surface
of the fiber - it never sees the jacket at all; only the losses,
and you'll never get them back anyway.

The jacket is for mechanical protection, but if all you want is
cosmetic, then you could paint the bare fiber.

Otherwise, either find something to dip it in like Plasti-Dip(tm),
or go ahead and thread the fiber through the tube of insulation
from a wire, or for that matter, spaghetti tubing, if you want
to go through all of that tedium.

Cheers!
Rich

 

If these fibers do not have any jacket at all, they may
depend on the low refractive index of surrounding air to
produce the total internal reflection that traps the light
inside the fiber. In that case, placing any material
against the fiber with a higher index of refraction will
increase the light leakage out of the fibers, unless it is
also highly reflective, like a metal coating.

You can easily test your fibers to see if they depend on
being surrounded by air, for their internal reflection, by
shining light through a piece, so that you can see or
otherwise measure the light output at the other end, and
then dip a loop of the fiber into water. If the output
drops, dramatically, then you will have to be careful with
what you place against the fiber.

 

Damn... I have all sorts of paint here and I didn't think of painting
the fiber..What a neat idea
I think the lead has gotten to me
D from BC

 

Fickn refraction depending on air...

Rich mentioned painting the cable.
So if I paint the cable..the refraction angle will change..IIRC the
refraction angle is reduced. This means the cable gets more selective
with increasing ray angles and there's more light loss.
Kinda like skipping stones on water..

You mentioned a metal coating...
I have aluminized mylar...I could make a reflective tape and wrap that
around the fiber.

I'm going to do some thinking
D from BC

 

A good possibility, unless the fiber is already made with two
different refrective indexlayers, with the total reflection happening
between them. With cheap plastic fibers, this is not necessarily the
case.

Yea, something like that.

I was thinking of evaporating metal onto the fiber in a vacuum, but
even a good mirror made this way has more loss than the total
refraction type reflection. It might look pretty, though. The fbers
would look like shiney wire.

Building a little test set up would be helpful. Couple a fiber to an
LED at one end and a photo diode or photo transistor at the other end
so you can measure the light being carried by the fiber. Then put
various stuff against the fiber and see how it reduces the light that
gets through. You will find that even bending the fiber more than
some minimum radius curve will let light escape at the bend.