• Skip to primary navigation
  • Skip to secondary navigation
  • Skip to main content
  • Skip to footer

FiberFin

Transforming the World to Polymer Optical Fiber

  • Industries
    • Industrial Manufacturing
    • Automotive
    • Military and Biometrics
    • Medical
    • Lighting
  • About
    • About FiberFin
    • FiberFin Capabilities
    • FiberFin Facilities
    • FiberFin Automation
  • FiberCast
  • News & Blog
  • Contact
  • Store
  • Industries
    • Industrial Manufacturing
    • Automotive
    • Military and Biometrics
    • Medical
    • Lighting
  • About
    • About FiberFin
    • FiberFin Capabilities
    • FiberFin Facilities
    • FiberFin Automation
  • FiberCast
  • News & Blog
  • Contact
  • Store
  • Store Home
  • Fiber and Cable
  • Hand Tools
  • Fiber Search
  • Connectors
  • Active Components
  • Cable Assemblies
  • Service/Warranty
    • Policies
    • RMA Request Form
    • eForce Service Information
    • eForce Service Request Form
  •  
Contact FiberFin

POF Measurement: Bandwidth

Bandwidth of Optical Fiber

Bandwidth describes the range of frequencies that can be transmitted through a channel, and consequently, the rate at which data can be transmitted through it.

Bandwidth of a fiber is an important factor when designing a fiber optic transmission system. It is defined as the range of frequencies from 0 Hz (DC) to the 3 dB frequency, where the light signal has been attenuated by 3 dB, or to half the transmitter power.

Frequency response plot of a fiber indicating its 3 dB bandwidth. Source: POF Handbook.

The relationship between bandwidth and data rate (symbol rate) can be generalized using Nyquist’s sampling theorem. It states that in a noiseless channel with bandwidth B, the data rate R can be calculated as twice the channel’s bandwidth.

Equations showing the relationship between data rate (R) and channel bandwidth (B).

For plastic optical fiber, bandwidth is dependent on the modal dispersion of the light signal in the fiber. This is affected by wavelength of light used, the light launching conditions, the fiber’s refractive index, and the run length of the fiber. By controlling these parameters, it can be reduced to achieve a particular bandwidth or data rate.

Bandwidth is also affected by a fiber’s index profile. Graded-index POF (GI-POF) limits the number of modes transmitted better than conventional step-index POF (SI-POF) does, which has the effect of continuously guiding the light towards the center of the fiber core. This reduces modal dispersion and consequently increases the bandwidth, which is almost double that of SI-POF.

Bandwidth Measurement

Measuring the bandwidth of large core fibers is difficult, and as a result, there is no standardized definition for it or the process. Experimental measurements are carried out using highly controlled parameters, such as light launch angle and the properties of transmitters and receivers. An RF network analyzer can be used in conjunction with photodiode amplifier and device to control the light source, as seen in the following figure..

Experimental bandwidth measuring setup. Source: POF Handbook.

References

O. Ziemann et al., POF Handbook. Berlin, Germany: Springer-Verlag Berlin Heidelberg, 2008.

Filed Under: FiberCast Tagged With: Advanced POF Topics, Measurement

Tariff Announcements – April 2025

Dear Valued Customers, We want to inform you that due to recent changes in tariffs, the prices of certain parts may experience an increase. Tariffs are taxes imposed on imported goods, and these changes can directly impact the cost of materials and pro …

Learn More

Footer

Contact FiberFin

FiberFin, Inc.
9925 State Route 47 Unit A
Yorkville, Illinois 60560
United States of America

+1 (630) 553-6924

Product support: info@fiberfin.com
Sales inquiries: sales@fiberfin.com

Visit the FiberFin Store

FiberFin offers a complete line of industrial-grade products, including POF cable, terminated cable assemblies, connectors, and accessories. To view our catalog or place an order, visit out our store. Visit the Store

Connect with FiberFin

  • Facebook
  • Pinterest
  • Twitter
  • YouTube
Privacy Statement
Terms & Conditions

Copyright © 2025 FiberFin · Website by Wicked Good Web