The refractive index in the core material of the fiber varies due to variation in the composition of the core material which give rise to two types of optical fibers. These are;

  1. Step Index fiber
  2. Graded Index fiber

Further, on the basis of guided optical signals, it can be categorized as

  1. Single mode step index optical fiber
  2. Multimode step-index optical fiber
  3. Multimode graded-index optical fiber

Single mode means the optical signal is parallel to the principal axis of the core of an optical fiber. While multimode means number of guided optical signals that enter through the acceptance cone and get multiple reflections inside the core.

Single mode step index optical fiber Multimode step-index optical fiber Multimode graded-index optical fiber
Core diameter 7-11μm 100-300μm 50-100 μm
Cladding diameter generally 125 μm 140-400 μm 125 to 150 μm
Buffer jacket diameter 500 to 1000 μm 400 to 1000 μm 400 to 1000 μm
Numerical Aperture 0.08 to 0.15 0.16 to 0.5 0.2 to 0.3
Performance 2-5 dB/km with a scattering limit of around 1 dB/km at a wavelength of 0.85 μm 2.6 -50 dB/km with a scattering limit of around 1 dB/km at a wavelength of 0.85 μm 2 – 10 dB/km with a scattering limit of around 1 dB/km at a wavelength of 0.85 μm
Bandwidth Greater than 500MHz km 6 to 50 MHz km 200MHz km to 3 GHz Km
Application These fibers are suited for high-bandwidth and medium to long haul applications using single-mode injection laser sources. These fibers are best suited for short distances, limited bandwidth, and relatively low-cost applications. These fibers are best suited for short haul and medium to high bandwidth applications (Local Area Network)