X2-10GB-LX4, minimal distance - could I use singlemode patchcord?

[Konstantin Gusenko]

I need to connect two 6506 with X2-10GB-LX4, they reside in adjacent racks, so the patch cord length is no more than 10 meters. The X2-10GB-LX4 documentation is not clear about SMF ranges, it only notes that

"Another alternative for short reaches within the same location is to use a single-mode patch cable. There will be no saturation over single-mode fiber. Please note the 10GBASE-LX4 devices can reach up to 10km over single-mode fiber as per compliance to IEEE.".

The MMF notes are much clearer, they say I can use OM2 MMF with mode conditioning patchcords and 5db 1300nm attentuators, also I could use OM3 MMF with same attentuators, but that's the configurations I'd prefer to avoid.

So could I just get an SMF patchcord and plug in to both tranceivers? Have I need to use attentuators or whatever else on such kind of link?

[Tom Randstrom · Accepted solution]

According to the documentation and the specifications, if you use SMF patch cables, you can plug the two LX4 transceivers together without any attenuators or mode conditioning patchcords. The maximum transmit power specification (-0.5dBm) of the LX4 transceiver is equal to the its maximum receiver input specification (-0.5dBm). 

The use of the LX4 transceiver for this short distance application is a very costly solution. The SX over MMF would be more economical. 

[Marvin Rhoads]

I agree with Tom on this.

Patch the two switches together via a an SMF jumper as noted in the Cisco documentation. Your Digital Optical Monitoring (DOM) features will be available and you'll be able to verify operation within specifications that Tom referred to.

[Konstantin Gusenko]

Thanks, Tom,

I know that LX4 tranceiver outprice the usual cost of such task's solution, but they're already in. If I'd was building that solution from the ground, I'd chose less expensive pair of tranceivers for sure.