LR vs SR SFP：What's the difference?

Small Form-factor Pluggable (SFP) modules, or transceivers, are devices used to interface between communication devices like switches and routers and the cabling that connects them. There are several types of these transceivers, each designed for specific networking needs and uses. Two of these types are LR (Long Range) and SR (Short Range) SFP transceivers, named and designed for the distance that they can successfully transmit data.

LR SFP: The term 'Long Range' is associated with SFP transceivers designed for long-distance transmissions. LR SFP modules typically use 1310 nm lasers and single-mode fiber optic cables which are designed for long-distance data transmission. They can transfer data securely between points over distances up to 10 km, or around 6 miles, and in some cases, with the use of an 'Extended Range - ER' SFP, it can go up to 40 km, offering a high-quality signal across large distances.

SR SFP: For its part, 'Short Range' refers to those SFP transceivers created for short distance transmission. SR SFP modules often use 850 nm lasers along with multimode fiber optic cables, intended for data transmission over shorter distances, typically up to 300 Long Range SFP, often denoted as SFP LR or SFP-LR, is a type of Small Form-factor Pluggable transceiver, which is designed for long-distance data communication. 

LR SFP transceivers are often used to transmit data over what's typically defined as longer distances which is generally over single-mode fiber optic cables. These types of cables are capable of transmitting data over significant distances with minimal signal loss, making them ideal for applications where devices are spread out over a wide geographical area, typically up to 10 kilometers, or approximately over six miles. Some Long Range SFP modules can even transmit data for up to 80 kilometers under the classification of 'Extended Range' or ER.

These modules function by converting electronic signals into optical signals for transmission over the fiber optic cables. Upon reaching the receiving end, they convert these optical signals back into electronic signals.

In terms of performance, LR SFP modules provide faster data transmission speeds and transmit over longer distances compared to Short Range SFP modules, but they are typically more expensive due to the use of laser technology and the cost of single-mode fiber cabling. 

They are commonly used in applications involving high-speed telecommunications networks, and anywhere robust and reliable long-distance data transmission is needed.

Comparison of appearance

Let us first look at the appearance of the SFP-10G-LR-S optical module and the SFP-10G-SR-S optical module. They are packaged in the form of SFP+ and can be plugged into the SFP+ port of the switch and are also hot-pluggable. The overall size is also the same. Because of different manufacturers, there are differences in the label position and interface design of the two optical modules, but the components are the same and there is no difference between them.

1、 The Same Points

The SFP-10G-LR-S optical module and the SFP-10G-SR-S optical module both have a rate of 10.3125 Gbps. Both of them can be applied to 10 Gigabit Ethernet, SDH and SONET networks, and their interface types are LC Duplex.

Both the SFP-10G-LR-S and SFP-10G-SR-S optical modules support the DOM function, which is digital diagnostics. It helps network administrators monitor and report the operating status of the optical module in real time, including the temperature of the optical module. , laser bias current, etc.

 

2、The Different Points

The wavelength of the SFP-10G-LR-S optical module is 1310nm, and the transmission distance can reach 10km when it is used with a single-mode optical fiber. And the wavelength of an SFP-10G-SR-S optical module is 850nm when it is used with an OM3 multi-mode optical fiber. The transmission distance up to 300m. Therefore, SFP-10G-LR-S optical module is mainly used for long-distance transmission, and the SFP-10G-SR-S optical module is only used for short-distance transmission. But they do not support FCoE link, it is recommended that everyone in accordance with the actual needs of the transmission distance could choose the right light module.

The laser type of SFP-10G-LR-S optical module is DFB 1310nm, whose transmitted optical power is -8.2 ~ 0.5dBm and the receiving sensitivity is <-14.4dBm. The laser type of SFP-10G-SR-S optical module is VCSEL 850nm whose transmitted optical power is -6 to -1dBm, and the receiving sensitivity is <-11.1dBm. The lasers of these two optical modules are different. The application range of DFB lasers is wider than that of VCSEL lasers. At present, the most commonly used lasers in the field of optical communications are FP lasers and DFB lasers. However, VCSEL lasers have not been widely used due to the disadvantages of complicated manufacturing processes and insufficient output power.

There are many manufacturers of SFP-10G-SR/LR, of which the representative is Cisco, and Cisco's switches also occupy a relatively large market share. But in the actual selection process, in addition to the IEEE standard and transmission distance, we also need to consider some other factors, such as compatibility and cost.

There are many Cisco SFP-10G-SR/LR optical modules manufactured by third-party manufacturers on the market, but they are not all compatible and may not be used in the SFP connector of the switch. When purchasing optical modules, It must be guaranteed that it is compatible with the switch.

The second factor is the cost problem. Many users will choose the original optical module. Of course, it is best if the funds are sufficient. The SFP-10G-SR/LR optical module offered by SOPTO has become a more and more popular choice due to its high cost-efficiency and good quality.

The above is simply to answer the question of what the next SFP-10G-SR/LR is. If you want to learn more about optical communications, welcome to Sopto Technology.

 

What do LR SFP and SR SFP represent respectively?

What is lr SFP?

Long Range SFP, often denoted as SFP LR or SFP-LR, is a type of Small Form-factor Pluggable transceiver, which is designed for long-distance data communication. 

LR SFP transceivers are often used to transmit data over what's typically defined as longer distances which is generally over single-mode fiber optic cables. These types of cables are capable of transmitting data over significant distances with minimal signal loss, making them ideal for applications where devices are spread out over a wide geographical area, typically up to 10 kilometers, or approximately over six miles. Some Long Range SFP modules can even transmit data for up to 80 kilometers under the classification of 'Extended Range' or ER.

These modules function by converting electronic signals into optical signals for transmission over the fiber optic cables. Upon reaching the receiving end, they convert these optical signals back into electronic signals.

In terms of performance, LR SFP modules provide faster data transmission speeds and transmit over longer distances compared to Short Range SFP modules, but they are typically more expensive due to the use of laser technology and the cost of single-mode fiber cabling. 

They are commonly used in applications involving high-speed telecommunications networks, and anywhere robust and reliable long-distance data transmission is needed.

 

What is Sr SFP?

Short Range SFP, often signaled as SFP SR or SFP-SR, is a Small Form-factor Pluggable transceiver designed for short-distance data communication over fiber optic cables.

SR SFP transceivers primarily use multimode fiber optic cables, which are ideal for relatively short-distance transmission, typically up to 300m or approximately 984 feet. Some SR SFP modules can support distance up to 2km depending on the specific model and data rate.

These transceivers operate by converting electronic signals into light signals for transmission over the fiber optic cable. Upon reaching the receiving end, the SR SFP transceiver, again, converts these light signals back into electronic signals that the receiving device can understand.

In the context of short distances, SR SFP transceivers can deliver high-speed data transmission and are typically less expensive than Long Range SFP modules, which makes them an ideal choice for local area networks (LANs) where devices are closely connected, such as in a single building or campus. This makes them a common choice for data center interconnections, enterprise wiring closets, or anywhere data needs to be quickly delivered over short distances.

 

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.