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I am using G.655 standard fiber for a project. We are using short haul SFP & long Haul SFP. Long haul (1550 nm) works fine with G.655 fiber, But Short haul SFP (1310 nm) is having some issue as link is not getting up. I am not sure whether the issue is coming because use of short haul at 1310nm.

Whether 1310nm wavelenght is support in G.655 fiber with cable cut off wavelenght?

Thanks for help in advance.

Regards, Vinay

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  • You don't say which SFPs or what distance you are using, but, for short haul, you may need attenuators if the distance is very short.
    – Ron Maupin ♦
    Sep 6 '15 at 6:11
  • It will be transceiver and distance constrained. G.655 fiber is designed to minimize dispersion in the 1510/1550nm range. The further outside the "zero" point, the worse dispersion may be. The length of the run magnifies the effect. If you have to correct ($$$$$) equipment, you can measure the distortion (and power, etc.)
    – Ricky
    Sep 6 '15 at 21:58
  • Did any answer help you? if so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you could provide and accept your own answer.
    – Ron Maupin ♦
    Aug 6 '17 at 18:09
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If your using Cisco switches/line modules/SFP's that support DOM from the cli do show interface transceiver detail command and it will show all of the power levels. If your hardware doesn't support DOM you will get an error message. Cisco 1310 -LH SFP don't support DOM. If out of spec it will put either a + or ++ if too hot or - if too low. Definitely have to have the correct SFP reach part or things will be unstable. On 1310 short runs on good fiber loss is very minimal. Very easy to blind the receive side of the optics.

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  • Hi bsulli, the receive power at SFP is -10 dBm & its sensitivity is -19dBm. But even having a power received, switch physical layer link is getting up. I doubt if G.655 ITU standard FO cable support 1310 nm wavelenght SFP.
    – Vinay Singh
    Sep 6 '15 at 15:05
  • Stand corrected. I was thinking about our single mode fiber which is ITU g.652, .655 does not support 1310nm cisco.com/c/en/us/products/collateral/interfaces-modules/… & ciscopress.com/articles/article.asp?p=170740&seqNum=7 last paragraph.
    – bsulli
    Sep 6 '15 at 15:56
  • I'm not convince that G.655 cannot be used for 1310 nm. Cable vendors seem to think it can, and I keep finding things like this: usable at 1310 nm wavelength and optimized for high bit rate transmission in C (1530 – 1565 nm) et L (1565 – 1625 nm) bands,.
    – Ron Maupin ♦
    Sep 6 '15 at 18:39
  • Don't disagree Ron as I had experiences where wavelengths worked on fiber that weren't suppose to but if the Cisco docs are to be believe they as a vendor don't support it 1310 on 655 fiber.
    – bsulli
    Sep 6 '15 at 19:18
  • Of course, the OP hasn't said which SFPs are being used for this, so we don't know for sure if they non-supported Cisco or some other brand/type.
    – Ron Maupin ♦
    Sep 6 '15 at 20:43
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G.655 fiber like Corning LEAF has a cutoff frequency of 1450nm. Thus if you launch a 1310nm signal it behaves as multimode fiber. It's diffucult to predict how these modes would be transmitted in this situation, but most likely the light won't reach the end if your transmitter isn't powerfull enough. There are some evidencies like this one http://www.gossamer-threads.com/lists/nanog/users/153261 where people make 1310nm sfp with optical budget for 40km to pass g.655 fiber of 10km.

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