[j-nsp] ACX5048 - 40 gbps ER 40 km optic

[Pavel Lunin]

2017-10-05 1:00 GMT+02:00 Aaron Gould <aaron1 at gvtc.com>:

> Thanks Pavel, Ok here it is.  Does this mean it should work ?
>
>
>
>   Lane 0
>
>     Laser bias current                        :  32.187 mA
>
>     Laser output power                        :  1.135 mW / 0.55 dBm
>
>     Laser receiver power                      :  0.000 mW / -40.04 dBm
>


As Sebastien mentioned above, this output means that you don't receive any
light. -40 dBm is just a fancy way to say "darkness". At the same time you
see some emitted power, this means you "send" light to the other end.
Check it on both sides: if A doesn't see what B emits or vise-versa, it
normally means you have a problem in the middle. Check your cabling (make
sure that it's not MMF :) NB: as 40GE is technically 4×10GE (wavelength
multiplexed in this case), you have four lanes for each port, this is why
it's called Quad-SFP and ER4.

When you manage to have the light on the other side of your fiber, you
might face another problem. As this is an ER, you can saturate your
receiver if you don't have enough attenuation. So either use an attenuator
or the above mentioned common trick with turning the fiber around your
finger to let the light escape through the cladding (fix it with tape). See
Chuck's comment for more details.

Or just replace the optics with a QSFP-DAC )