does fiber optic waste energy?

Hi, I am working on a optical project and I need to bend a light 90 degrees at one point. I was thinking of using fiber optic wires for that. However, the system should be really energy efficient, and since i have never worked with fiber optics i was just wondering will fiver optics decrease light's energy significantly within transmission? do they waste lights (photon) energy? thanks

Yes. Fiber optics use energy with some inefficiency. After a 1 kilometer fiber length, the light is dimmer. It is not as wasteful as a steam locomotive

No material is free of resistance, whether that be electrical or optical transparency. That said, the point of fiber optics is not usually to carry energy in the traditional sense, so as long as the light remains visible enough for its purpose, then it's good enough.

If you're using it as a data transmission mechanism, and assuming you're not going across spans of land (you said one 90-degree turn, not "into the adjacent valley and through the other side of the mountain range"), any material designed for optics is likely to be far beyond sufficient.

OTOH, if you're hoping to light your house from a single centrally located light bulb and a bunch of fiber optic cables, you might face some engineering challenges. Although, that one corner bend may not be the pinnacle of said challenges. :D

If it's just a simple corner less than 3 cm or so perhaps 4 cm there are "Light Pipes" just for that purpose. An example would be an SMD LED on a PCB and the light pipe to "bend" it @ some desired angle to match a front panel of a box or cabinet or just to move it in line with other LED's. An efficient LED and a very little current is commonly used.

Doc

Most of the energy loss is in the coupling from light source into the light pipe. A pulse sent down fibre optics turns into a shape called a soliton, this can travle long distances with almost no reduction in amplitude.