Acceptance Angle in Optical Fibre Calculation

The system calculate the acceptance angle of an optical fiber.





The acceptance angle is the maximum angle at which light-ray enters or hits the fiber core and getting propagate though it in zig-zag path.

The acceptable angle is also called the numerical aperture therefore it is determined by the refractive index contrast between core and cladding of the fiber with assumption that the incident beam comes from air or vacuum.


θm = sin-1((1/ηo) * (ηf2c2)1/2)


θm = Acceptance Angle,

ηo = Exterior Refractive Index,

ηf = Fibre Refractive Index,

ηc = Cladding Refractive Index


Important to know about OTDR

An optical time domain reflectometer (OTDR) is a device used to detect the faults in an optical fiber link of a communication network. It sends short pulses of light across a fiber.

Light scattering occurs in the fiber due to discontinuities such as connectors, splices, bends and faults.

The OTDR then detects and analyzes the back-scattered signals. Signal strength is measured for specific intervals of time and is used to characterize events.