Question for the SFP 10G about the minimum operating distance of SFP 10G?

Dear Support,
I would like to ask about the minimum operating distance of SFP+—specifically, the shortest possible distance, not the maximum. At what distance can SFP+ start functioning? I couldn’t find this information in the datasheet or installation guide, but I really need to know. The models I am considering are as follows:

RJE-XG-SFP-SR-MM850

RJE-XG-SFP-LR-SM1310

RJE-XG-SFP-ER-SM1550

Before The issue I encountered was when I tested an 80 km module (Not Ruijie Brand) at a distance of 100 meters, and it did not work. I ended up wasting my purchase. Therefore, I need to ask Ruijie for clarification in advance to ensure I have accurate information.

Thank you and Best Regard.

Dear Victor,
Thank you for reaching out with your inquiry regarding the minimum operating distance of SFP+ modules. We understand the importance of ensuring compatibility and functionality for your deployment needs.
Regarding the models you mentioned (RJE-XG-SFP-SR-MM850, RJE-XG-SFP-LR-SM1310, and RJE-XG-SFP-ER-SM1550), we are currently confirming the minimum operating distance and related technical details with our R&D team.
Once we have a clear and precise response, we will provide you with the necessary information to help you make an informed decision. We appreciate your patience and will get back to you as soon as possible.
Please feel free to reach out if you have additional questions or concerns in the meantime.

Dear Victor,

After consulting with our R&D team, we regret to inform you that specific data on the minimum operating distance for these models (RJE-XG-SFP-SR-MM850, RJE-XG-SFP-LR-SM1310, and RJE-XG-SFP-ER-SM1550) is not documented in our current specifications.
That said, we would like to understand your requirements better. Could you kindly share the minimum distance you plan to use these modules over? This will help us evaluate your use case and recommend suitable options or potential solutions, such as the use of optical attenuators, if applicable.
We are committed to supporting you in finding the best solution for your setup. Please feel free to provide more details, and we’ll assist you further.

GTAC-Ryan replied at 2024-11-27 09:10
Dear Victor,

After consulting with our R&D team, we regret to inform you that specific data on the  ...

Dear Support,

The fiber distance you are asking about is double checked.

Thank you and Best Regard.

Victor replied at 2024-11-27 11:08
Dear Support,
The fiber distance you are asking about is double checked.

Dear Victor,
Thank you for your inquiry regarding the minimum operating distance of SFP+ modules. After reviewing your request, we would like to provide the following information about the models you mentioned:

RJE-XG-SFP-SR-MM850 (300m):

• This module does not have a minimum distance limitation and can be used for distances up to 300 meters.
  

RJE-XG-SFP-LR-SM1310 (10km):

• This module also does not have a minimum distance limitation and is suitable for distances up to 10 kilometers.
  

RJE-XG-SFP-ER-SM1550 (40km):

• This module has a receiver overload point of -1 dBm. For very short distances, if the received optical power exceeds this value due to minimal fiber attenuation, you may need to use an optical attenuator to reduce the signal strength.
• Considering a typical fiber attenuation coefficient of 0.25 dB/km, this module is recommended for distances over 10 kilometers to avoid overload risks. For shorter distances (below 10 km), we suggest adding a 5 dB optical attenuator to prevent signal issues.
  

Our Recommendations Based on Distance:
For distances around 0.13 km: Use RJE-XG-SFP-SR-MM850 (300m)
For distances between 0.33 km and 8.06 km: Use RJE-XG-SFP-LR-SM1310 (10km).
For distances between 13.26 km and 20.80 km: Use RJE-XG-SFP-ER-SM1550 (40km).
If you have additional requirements or specific scenarios you'd like us to evaluate, feel free to let us know. We’re here to assist you in selecting the most suitable module for your needs.
Best regards.