Lighting Fundamentals: Fiber Optics
Fiber optics, or "wave guides," are specially-fabricated threads of plastic, quartz or other transparent material created to direct a narrow beam light from point A to B. It's used mostly for communications, but also specialized scientific equipment and suchlike.
For modeling purposes, fiber optics may be more useful than you might realize, but less useful than others may have you believe. Although they have only a few ideal applications, fiber optics excel at them.
One big myth is that fiber optics can be used for general illumination. Yes, it is possible, but woefully impractical. That's because the light emerging from a fiber is very focused, spreading out only a few degrees. It's possible to put some sort of diffuser on the ends to spread the light out more, but then you hit the other limitation: fiber optics are not very efficient. You can pump only just so much light through a fiber. A few pennies' worth of wire and LEDs can set a city block ablaze.
Having said all of that, because it is highly directional, fiber optics are perfect for simulating certain specific lighting effects; in particular, vehicle headlights. Install a pair of fibers in a model car, place it at a grade crossing, and watch the magic as the "headlights" shine on the passing freight cars.
Fiber optics are also great for creating tiny pinpoints of light wherever you might need them. Use them for marker lights on tractor trailers (still smaller than the smallest LEDs). Or, in my case, they create delightfully realistic fireflies.
Save yourself some money: for a few bucks you can purchase a few yards of prime new fiber. Or, spend the same few bucks on a cheap fiber optic room light, such as this:
You'll get dozens of yards of fiber with one of these. The only issue is that the fibers are about a foot long each, but that's still useful in most cases; it's rare you'd need single fibers as long as a yard.