If a particular optical power is coupled from an incoherent LED into a low-NA fiber, the device must exhibit very high radiance .

Question

Quizplus · Accepted Answer

The radiance of an optical source is defined as the optical power emitted per unit area per unit solid angle. For a low-NA fiber, the solid angle of acceptance is small, so the radiance of the source must be high in order to couple a significant amount of optical power into the fiber.

If a Particular Optical Power Is Coupled from an Incoherent