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Community Member

How many ‚„‚a‚is it?

Hi.

wavelength:1310 nm

9 microns and single mode

distance :10Km

How many ‚„‚a‚ is attenuate of optical? (reference value)

2 REPLIES
Cisco Employee

Re: How many ‚„‚a‚is it?

Well, this is difficult to answer as it will depend on the fiber used and its own dispersion and attenuation properties.

Gold

Re: How many ‚„‚a‚is it?

Typical SMF cable attenuation at 1310nm wavelength is 0.3 to 0.5dB/km. The actual value should be obtained from the cable manufacturer. I use 0.4dB/km for calculating expected loss over the spans we build.

For a hypothetical 10km run, total attenuation expected would be:

cable attenuation of 4.0dB (10km * 0.4dB/km); plus

connector pair loss of 3.0dB (1.0dB per pair, or 0.5dB per connector); plus

splice loss of 0.4dB (0.1dB per fusion splice);

equals 7.4dB.

This is within the 1000BASE-LX/LH GBIC's power budget of 9.5dB.

This fiber span consists of a 2-meter patch cable at each end (with each patch cable having a pair of connectors); and 9.996km of SMF with four fusion splices along its length (and a connector at each end, located in a fiber patch panel).

Cisco has a page which is helpful in illustrating the concept:

Calculating the Maximum Attenuation for Optical Fiber Links

http://www.cisco.com/warp/public/127/max_att_27042.html

And Corning has a neat on-line Link Loss Budget Worksheet:

http://www.corningcablesystems.com/web/privnet/webapp.nsf/linkloss?OpenForm&Seq=9

This is probably a little late to help the original poster; but hopefully it will help somebody.

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