Fiber loss

[Eric Lindsey]

We have a new site coming online connected to our core network. The site is 4 miles away and we have dark fiber. We are connecting dual 10Gb links and are using 10g-lr-s sfps. The core has 6509s and the site is using 3850s. There is an Lc-Lc fiber patch cable on each side.  When I run the tranceiver details command on the tengigabit interfaces the receive strength is around -16dBm. How much will that value affect the traffic?  The value is the same in the 6509s as in the 3850s. 

[Reza Sharifi]

With -16dbm you should be fine.

What power level should a source have?
It depends on the type of source. When coupled into a good test cable, the source output power will be in these ranges:
LED: -10 to -25 dBm into 62.5/125 fiber
Telcom/LAN laser: 0 to -13 dBm into singlemode fiber, to +20 dBm with DWDM and fiber amplifier systems
CATV Laser : +16 to 0 dBm into singlemode fiber

What power level should a receiver see?
It depends on the network and type of source. When measured at the end of the network cable, the source output power will usually be in these ranges:
LAN/LED: -20 to -35 dBm into 62.5/125 fiber
Telcom/LAN laser: -20 to -45 dBm into singlemode fiber
CATV Laser : 0 to -10 dBm into singlemode fiber

http://www.thefoa.org/tech/FAQS/FAQ-TEST.HTM

HTH