RE: MultiMode Fiber Connectivity... (850nm) Power Question
Usually on Multi-mode and Low-power single-mode optics the MaxOutputOpticalPower is less than or equal to the MaxInputOpticalPower, so it's not necessary to attenuate. The trade-off is optimized optics versus having an attenuator sticking out the front of the electronics. Something along the lines of -9.5 to -4 transmit power and -18 to 0 on the Receive power. Multi-Mode optics tend to be more application specific than single-mode A good rule of thumb is keep a minimum of 4dB off the bottom plus 20% of the optical budget, discounting any specific application the above optic would be optimal around -10dB. Daniel Jameson Manager - IP Network Engineering TDS Telecom -Original Message- From: NANOG [mailto:nanog-boun...@nanog.org] On Behalf Of Faisal Imtiaz Sent: Wednesday, February 11, 2015 2:48 PM To: NANOG Subject: MultiMode Fiber Connectivity... (850nm) Power Question Hello, I was looking for feedback on the following question:- When connecting two MM SFP/SFP+/XFP 's together...(short range). What should be the best practice receive power range ? Is it true that if the rx power is higher than (x?) then it shortens the life of the optics ? (assumption being made here is that MAX Rx Power is not being exceed as per the spec sheets of the optics) Regards Faisal Imtiaz Snappy Internet & Telecom 7266 SW 48 Street Miami, FL 33155 Tel: 305 663 5518 x 232 Help-desk: (305)663-5518 Option 2 or Email: supp...@snappytelecom.net
Re: MultiMode Fiber Connectivity... (850nm) Power Question
Thanks Justin... Faisal Imtiaz Snappy Internet & Telecom 7266 SW 48 Street Miami, FL 33155 Tel: 305 663 5518 x 232 Help-desk: (305)663-5518 Option 2 or Email: supp...@snappytelecom.net - Original Message - > From: "Justin M. Streiner" > To: "NANOG" > Sent: Wednesday, February 11, 2015 12:41:23 PM > Subject: Re: MultiMode Fiber Connectivity... (850nm) Power Question > > On Wed, 11 Feb 2015, Faisal Imtiaz wrote: > > > I was looking for feedback on the following question:- > > > > When connecting two MM SFP/SFP+/XFP 's together...(short range). > > > > What should be the best practice receive power range ? > > SX (1G) / SR (10G) / SR10 (100G) gear generally has a receive threshold > that's higher than the maximum launch power. They are designed for > short-reach applications (in-building, data center, etc), so no > attenuation is needed. > > > Is it true that if the rx power is higher than (x?) then it shortens > > the life of the optics ? > > (assumption being made here is that MAX Rx Power is not being exceed as > > per the spec sheets of the optics) > > On short-reach optics, this should never be a problem. On long-reach > optics, receiver saturation will generally result in link errors/flaps, > and possibly high rx power warnings (depending on the gear on the > receiving end), however, these can be addressed using in-line attenuators. > > On very long-reach optics, such as ZX (1G) and ER/ZR (10G), it is possible > to damage the receivers with too hot of a signal because they are designed > for long spans and a certain amount of distance-based attenuation is > factored into the optical power budget. > > jms >
Re: MultiMode Fiber Connectivity... (850nm) Power Question
On Wed, 11 Feb 2015, Faisal Imtiaz wrote: I was looking for feedback on the following question:- When connecting two MM SFP/SFP+/XFP 's together...(short range). What should be the best practice receive power range ? SX (1G) / SR (10G) / SR10 (100G) gear generally has a receive threshold that's higher than the maximum launch power. They are designed for short-reach applications (in-building, data center, etc), so no attenuation is needed. Is it true that if the rx power is higher than (x?) then it shortens the life of the optics ? (assumption being made here is that MAX Rx Power is not being exceed as per the spec sheets of the optics) On short-reach optics, this should never be a problem. On long-reach optics, receiver saturation will generally result in link errors/flaps, and possibly high rx power warnings (depending on the gear on the receiving end), however, these can be addressed using in-line attenuators. On very long-reach optics, such as ZX (1G) and ER/ZR (10G), it is possible to damage the receivers with too hot of a signal because they are designed for long spans and a certain amount of distance-based attenuation is factored into the optical power budget. jms
Re: MultiMode Fiber Connectivity... (850nm) Power Question
Thank you guys (Bob, Brandon & Eric) for the prompt answer. Regards. Faisal Imtiaz Snappy Internet & Telecom 7266 SW 48 Street Miami, FL 33155 Tel: 305 663 5518 x 232 Help-desk: (305)663-5518 Option 2 or Email: supp...@snappytelecom.net - Original Message - > From: "Bob Evans" > To: "Faisal Imtiaz" > Cc: "NANOG" > Sent: Wednesday, February 11, 2015 4:06:23 PM > Subject: Re: MultiMode Fiber Connectivity... (850nm) Power Question > > > Thank You > Bob Evans > CTO > > > > > > Hello, > > > > I was looking for feedback on the following question:- > > > > When connecting two MM SFP/SFP+/XFP 's together...(short range). > > > > What should be the best practice receive power range ? > > > > Is it true that if the rx power is higher than (x?) then it shortens the > > life of the optics ? > > Yes, but thats only true about single mode frequencies not multimode (MM) > because those are not as powerful. All MM is expected to go a very limited > distance, so levels are never high. We have MM 3 foot jumpers between gear > running for years. > > > (assumption being made here is that MAX Rx Power is not being exceed as > > per the spec sheets of the optics) > > > > Regards > > > > Faisal Imtiaz > > Snappy Internet & Telecom > > 7266 SW 48 Street > > Miami, FL 33155 > > Tel: 305 663 5518 x 232 > > > > Help-desk: (305)663-5518 Option 2 or Email: supp...@snappytelecom.net > > > > >
Re: MultiMode Fiber Connectivity... (850nm) Power Question
Faisal, You don't need to worry about power range when connecting SR or LR. However, an ER or ZR on a loopback can damage Rx. The strength of the receiving signal is always under the tolerance allowed. The 850nm Light is attenuated very quickly because of the MMF and the 850nm light source. This light source is more like an LED than a Laser. The MTTF on any transceiver is 50,000 hours at room temperature. A bigger factor is high temperature, because the chip is a semiconductor. Eric Litvin President e...@lumaoptics.net Direct: (650)440-4382 Mobile:(*650)996-7270* Fax: (650) 618-1870 On Wed, Feb 11, 2015 at 12:48 PM, Faisal Imtiaz wrote: > Hello, > > I was looking for feedback on the following question:- > > When connecting two MM SFP/SFP+/XFP 's together...(short range). > > What should be the best practice receive power range ? > > Is it true that if the rx power is higher than (x?) then it shortens the > life of the optics ? > (assumption being made here is that MAX Rx Power is not being exceed as > per the spec sheets of the optics) > > Regards > > Faisal Imtiaz > Snappy Internet & Telecom > 7266 SW 48 Street > Miami, FL 33155 > Tel: 305 663 5518 x 232 > > Help-desk: (305)663-5518 Option 2 or Email: supp...@snappytelecom.net > -- Eric Litvin President e...@lumaoptics.net Direct: (650)440-4382 Mobile:(*650)996-7270 <650%29996-7270>* Fax: (650) 618-1870
Re: MultiMode Fiber Connectivity... (850nm) Power Question
Thank You Bob Evans CTO > Hello, > > I was looking for feedback on the following question:- > > When connecting two MM SFP/SFP+/XFP 's together...(short range). > > What should be the best practice receive power range ? > > Is it true that if the rx power is higher than (x?) then it shortens the > life of the optics ? Yes, but thats only true about single mode frequencies not multimode (MM) because those are not as powerful. All MM is expected to go a very limited distance, so levels are never high. We have MM 3 foot jumpers between gear running for years. > (assumption being made here is that MAX Rx Power is not being exceed as > per the spec sheets of the optics) > > Regards > > Faisal Imtiaz > Snappy Internet & Telecom > 7266 SW 48 Street > Miami, FL 33155 > Tel: 305 663 5518 x 232 > > Help-desk: (305)663-5518 Option 2 or Email: supp...@snappytelecom.net >
