How many modes are currently in used for propagating light along an optical channels?a.Five modesb.One modec.Two modesd.Three modes

The number of modes used for propagating light along optical channels depends on the type of fiber.

In single-mode fibers, only one mode (b. One mode) is used. This type of fiber provides one path, or mode, for light rays to travel, typically straight down the middle of the fiber. This allows the signal to travel a longer distance without losing its strength.

In multimode fibers, multiple modes (more than one) are used. This type of fiber provides multiple paths for light rays to travel. However, signals sent over long distances can become distorted because of the different paths the light rays can take.

So, the answer could be either b. One mode (for single-mode fibers) or more than one mode (for multimode fibers). The exact number for multimode fibers can vary, but it's typically more than two.