The meaning of SR, LR, LRM, ER, and ZR in Transceiver Modules

When you take transceiver modules, all of this will contain many abbreviations which may be quite confusing for you too. In fact, these abbreviations tell you the characteristics of these modules. Let us have a look into some of this in detail.

SFP-10G-SR vs SFP-10G-LR vs SFP-10G-LRM vs SFP-10G-ER vs SFP-10G- ZR is the most common scene abbreviations in almost all SFPs. What are the similarity and differences? Now let us make a comparison of the similarity and difference, it will help you choose the right 10G SFP+ module depends on your application.

When you are looking at these terms SR, LRM, LR, ER, ZR used in fiber optic communications that stand for the transmission distance of these modules. Here we have considered only 10Gbps SFPs only to learn about its transmission capacity.

Let us see that the case of Multimode Fiber

10GBase-SR

SR stands for Short Range, these transceivers support link length of 300m over multi-mode fiber and use 850nm lasers. 10GBase-SR is the original multimode optics specification and is still by far the most commonly used.  

10GBase-SR it uses a single, low-cost solid-state laser assembly, it is also the least expensive of the optical modules available for a 10GbE platform. However, 10GBase-SR is very sensitive to fiber type. Its Physical Coding Sublayer 64b/66b PCS is defined in IEEE 802.3 Clause 49 and its Physical Medium Dependent PMD in Clause 52. It delivers serialized data at a line rate of 10.3125 Gbit/s.

10GBase-LRM

LRM means Long Reach Multimode, these transceivers support distance up to 220m over multi-mode fiber and use 1310nm lasers. The replacement to 10GBase-LX4, 10GBase-LRM will reach up to 220m over standard multimode fiber, but without the complexity of the 10GBase-LX4 optics.  Instead, a single laser operating at 1310nm is used.  This allows LRM optics to be packaged in XFP and SFP+ form factors.

Let us see that the case of Single-mode Fiber

10GBase-LR

LR means Long Reach, these transceivers support distance up to 10km over single-mode fiber and use 1310nm lasers.  There is no minimum distance for LR, either, so it is suitable for short connections over single-mode fiber as well. 

10GBase-ER

ER means Extended Reach, Basically, these are just extremely long-range fiber variations. 10GBASE-ER has a reach of 40 kilometers over-engineered links and 30 km over standard links. Due to the laser power, attenuation is required for links less than 20km long.

10GBase-ZR

ZR also stands for Extended Reach which can transmit a 10Gbps data rate and 80km distance over single-mode fiber and use 1550nm lasers. Due to the very high transmit power, significant attenuation is needed for shorter links. ZR is actually an unofficial format, which is not technically part of the IEEE 802.3ae standards for networking hardware. Use of ZR optics should be preceded with an optical power test of the fiber span in question to ensure a problem-free deployment.  Several hardware manufacturers -including Cisco- have their own implementations of ZR, but they aren't necessarily cross-compatible. 

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