S.I. Tech, Inc.

Technical Support

     

To Contact Technical Support

  Problem


Email:
Tech@sitech-bitdriver.com
Phone: 630-761-3640


Web Site Content

 


Is data rate a function of fiber optic cable length?

Solution

  • Fiber optic cable has bandwidth limitations, normally specified as MHz/km. For example:

62.5/125 multimode fiber 200 MHz/km @ 850 nm
  500 MHz/km @ 1300 nm
50/125 multimode fiber 600 MHz/km @ 850 nm
8.5/125 single mode fiber Several GHz/km @ 1300 nm or 1550 nm

To determine maximum distance your data can travel, divide bandwidth by data rate. For example:

62.5/125 fiber - 200 MHz/km @ 850 nm / 20 Mbps = 10 km max

Besides bandwidth, you need to consider attenuation (loss) normally express as dB/km @ a given wavelength (850/1300/1550)

62.5/125 fiber - 3.5 dB/km @ 850 nm

Therefore, for 10 km, you will have 35 dB loss which is beyond power budget of most fiber optic transmitter/receivers. So practically, 5 km or 20 dB is maximum limit.

Previous

Back to Technical Support
©2003 S.I. Tech, Inc. All copy and images.