A good general rule of thumb for optics is +-4. Try to stay 4 db off the bottom, and 4db off the top. The sweet-spot RSL is between 1/2 and 2/3 of the optical budget. For PON, typical OLT/ONT optics run Receive Max of -8, and Min of -27 with an optical de-assert at -31. The sweet-spot is between -17 and -20, with a min/max of -12 to -23. A typical PON system will have a TX power between +3 and +5, with a 32 way split, add 15dB of insertion loss. You should see -12 on the output of the first splitter (less the optical loss of the fiber between the OLT and the Splitter est .3/km) There should never be a need to attenuate a PON port unless you're working directly on the OLT (You should work through a splitter even directly in the CO/HE) -----Original Message----- From: NANOG [mailto:nanog-bounces@nanog.org] On Behalf Of Colton Conor Sent: Monday, October 12, 2015 10:58 AM To: NANOG Subject: Re: GPON Optical Levels Here is the link to the attachment as it looks like the list does not allow uploading attachment: https://drive.google.com/file/d/0B7sFULLCnLvFdllHQUl6dnJfZ00/view?usp=sharin... On Mon, Oct 12, 2015 at 10:47 AM, Colton Conor <colton.conor@gmail.com> wrote:
We are deploying our first GPON network, and are trying to get a sense of what is a good optical level per ONT. The equipment install guide says the following:
Measure the levels of the 1550 dBm and 1490 dBm receive optical inputs using
an optical power meter. The input range should be between -27.0 dBm to -8
dBm.
Attached are the measurements I can see and graph from the ONT side. Trying to get a sense of what range we would graph as good (green) measured within the clear, what we could consider yellow as working but out of optimal range, and what we could consider poor (red) range.
What about the Laser Bias Current, Optics Module Voltage, and Optics Module temperature?