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Fiber Minimum Length and/or SFP Attenuation for Staging

Occasional Contributor

Fiber Minimum Length and/or SFP Attenuation for Staging

We are building a six-site, routed network with multiple loops for our Customer, employing MSR routers over fiber and Ethernet microwave links.  For the fiber links, we're using original JD061 LH40 transceivers.

To stage the network and build the configurations in our office, we plan to connect the fiber interfaces locally with short (20ft) jumpers. Naturally, we are concerned about the possibility of optical burnout with the SM LH40 optics.

What is the minimum fiber length that should be used with the JD061 to prevent burnout?

Are any commands available under Comware to reduce the power of the JD061?  Or is that done automatically?

Suggested methods for increasing the attenuation in the jumpers?

Or do we need to bite the bullet and buy a dozen cheap, off-brand SM optics for staging?

Thanks for any solutions or suggestions,


Honored Contributor

Re: Fiber Minimum Length and/or SFP Attenuation for Staging

The proper way to do this is to buy attenuators. They don't cost much.

The dirty way to do this is to get a rod and very tightly wind a 20m patch lead around it, then run your link through that.

In reality, for build purposes, I would just use copper ports to connect them temporarily. Buying SR transceivers means you haven't tested the real optics anyway.