Question

the condition for propagation of light in a fiber is given by Delta is equal to launch angle​

Answer 1

In optical fibers, propagation of light is due to internal total reflection.

Explanation:

• Total internal reflection causes the propagation of light in optical fibres. Light is refracted inside an optical fibre when it strikes one end of the cable.
• The light ray is refracted and strikes the coating-fiber contact at an angle larger than the critical angle.
• If the fibre is rounded and curved, the light traverses the complete length of the fibre and reaches at the other ends of the fibre without any reduction in intensity.

The conditions for light propagation

It requires the following two conditions:

• Light must move from denser to rarer materials.
• The incidence angle must exceed the critical angle.

#SPJ3

Answer 2

Answer:

The critical angle is the angle of incidence at which the light refracting waves that propagate perpendicular to the interface and the angle of  refraction reaches 90° if n1>n2 at that angle of incidence.

Internal total reflection is responsible for the transmission of light in optical fibers.

Explanation:

A tiny proportion of the electromagnetic field enters the area of a lower refractive index during the total internal reflection (TIR) of light through an optical fiber or a planar optical waveguide, creating a subwavelength field that massively decays as a measure of the distance from the fiber or phased array surface.

Light does not just travel along the core section of an optical fiber; it also partially travels over the cladding layer.

Total internal reflection is described as the phenomena that happens when light rays move from one medium with a higher optical density to one with a lower optical density.

Total internal reflection is the considering the quality of a light ray from the outer surface back into a medium, such as glasses or liquid, in optics. If the incidence angle exceeds a specific limitation angle known as the critical angle, the phenomena will manifest.

The light ray is bent and comes into contact with the coating at an angle that is greater than the critical angle. If the fiber is spherical and curved, the light travels its full length and arrives its other ends while experiencing any intensity loss.

The radius of the core, its numeric aperture, and the wavelength of the light activating the fiber all play a role.

#SPJ3