Coupling loss in fiber optics refers to the power loss that occurs when coupling light from one optical device or medium to another.

One may imagine an optical device that allows radiative heat transfer between the two cavities, filtered to pass only a definite band of radiative frequencies.

Electromagnetic wormholes, as an optical device (not gravitational) are derived from cloaking theories has potential applications for advancing some current technology.

The key development lies in the ability of the sphere, an optical device, to not only remain invisible itself but to slow light.

The physical length of an optical device can be reduced to less than the length of the optical path by using folded optics.