Q6. A step-index optical fiber has core refractive index 1.50, cladding refractive index 1.45, and core diameter 3 µm. The wavelength of light propagating in the fiber is 1.56 µm. Calculate the V-number and comment if it supports single-mode or multimode propagation.
Key Points:
- V-number (normalized frequency) determines propagation mode in optical fibers.
- Numerical Aperture (NA) measures light-gathering ability; NA = √(n₁² - n₂²).
- V-number formula: V = (π × d × NA) / λ.
- Calculated NA for the fiber is approximately 0.384.
Answer: Optical fibers are fundamental components in modern communication systems, guiding light over long distances. The propagation characteristics of light within an optical fiber, specifically whether it supports single-mode or multimode propagation, are critically determined by a dimensionless parameter known as the V-number or normalized frequency. This value quantifies the number of modes that can be supported by the fiber for a given wavelength of light. To determine the V-number, we first need...