Fiber optics has revolutionized the way we transmit information over long distances. Optical fibers are used to transmit light signals over long distances with minimal signal loss.
These fibers come in two main types: step-index and graded-index optical fibers.
One of the major difference between a step index fiber and a graded index fiber is that,
A step index fiber has a core with constant refractive index and make a step change from the core – cladding interface.
Whilea graded index fiber does not have a core with constant refractive index, and it makes a gradual change from the core – cladding interface.
In this blog post, we will explain the differences between these two types of optical fibers.
Step-index optical fiber is the most common type of optical fiber. It consists of a core made of a single material, surrounded by cladding material of lower refractive index.
The core and cladding have different refractive indices, which causes light to be reflected back into the core when it reaches the interface between the core and cladding.
This allows the light to be transmitted along the fiber with minimal signal loss. The refractive index of the core is usually higher than that of the cladding.
The diameter of the core can vary depending on the application, but is typically around 10 micrometers. The cladding is usually made of a material with a lower refractive index, such as silica.
Graded-index optical fiber is a type of optical fiber that has a continuously varying refractive index profile from the center of the fiber to the edge (in a gradual process).
The core of the fiber is made of a material with a high refractive index, which gradually decreases towards the edge of the core.
This creates a smooth transition of the refractive index, which allows the light to travel through the fiber in a curved path, minimizing modal dispersion.
The diameter of the core is typically around 50 micrometers, which is larger than the core diameter of step-index fibers.
The cladding is usually made of a material with a lower refractive index than the core, such as silica.
|s/n||Step Index Fiber||Graded Index Fiber|
|1||Refractive Index||It has a constant core refractive index||It does not have a constant core refractive index|
|2||Index Profile||The refractive index profile makes a step change at the core-cladding interface||The refractive index profile makes a gradual change at the core-cladding interface|
|3||Mode||Step index occur in single mode fiber and multimode fiber||Graded index occur in multimode mode fiber only|
|4||Propagation Path||Light propagates in step index fiber in a zigzag form||light rays propagates in a skew or helical form|
|5||Dispersion||Step index fibers have higher dispersion||Graded index fibers have lower dispersion|
|6||Cost||Step index fibers are simple and less expensive to manufacture||Graded index fibers are more expensive to manufacture|
|7||Numerical aperture||Step index fibers have a higher numerical aperture||Graded index fibers have a lower numerical aperture|
|8||Transmission Performance||Step index fibers have less transmission performance||Graded index fibers have a better transmission performance due to the lower dispersion and reduced reflection|