| 释义 |
coupling efficiency The efficiency with which a light source physically connects to an optical fiber. The more precisely the light source can inject a tightly focused signal directly into the inner core of a fiber, the stronger the resulting signal and the better the signal performs over a distance. Coupling efficiency is a key advantage of pairing a diode laser with a single-mode fiber (SMF), which has an inner core of only 5–10 microns. A less sophisticated light-emitting diode (LED) is incompatible with SMF as the emitted optical signal is too crudely focused and, therefore, would overfill the fiber core. LEDs are designed to mate with multimode fiber (MMF), which has a thicker inner core.The level of inefficiency, or coupling loss, is described as insertion loss, as measured in decibels (dB). See also core, coupling loss, dB, insertion loss, laser diode, LED, MMF, signal, and SMF. 74570c03.qxd 9/11/07 12:19 PM Page 115 |