In
fiber optics, the efficiency of optical
power transfer between two optical components. (
188 ) [After
2196] Note 1: The transfer may take place (a) between an active
component, such as an LED, and a passive component, such as an
optical fiber, or (b) between two passive components such as two optical fibers. Note 2:
Coupling efficiency is usually expressed as the ratio, converted to percent, of the
input power, i.e., the available power from one component, to the power transferred to the other component.