In today's rapidly developing information age, data centers and network communications have an increasing demand for high-speed and stable data transmission. As a key component to meet this demand, 25G optical modules have been widely used in the market. Among them, SFP-25G-SR and SFP-25G-ESR in 25G multimode optical modules are two common types. Let's take a closer look at their differences.

1. 25G Multimode Optical Module Overview

25G multimode optical modules are mainly used for short-distance data transmission, with high transmission rate and cost performance. They usually use multimode optical fiber for signal transmission and are suitable for connections between devices within data centers, such as switches, routers, network interface cards (NICs) and storage network devices.

1) SFP -25G-SR optical module adopts the hot-swappable SFP28 package, with an operating wavelength of 850nm. It is a full-duplex transceiver module. It is designed for short-distance data transmission and is usually used with OM3 or OM4 multimode optical fiber. The transmission distance can reach 70 meters to 100 meters and supports DDM function.

2) SFP -25G-ESR also uses SFP28 packaging, has hot-swappable features, and is also a full-duplex transceiver module. The ESR module is designed to be used with OM4 multimode optical fiber, supports longer transmission distances, can achieve a maximum transmission distance of up to 300 meters, and supports DDM function.

2. The main differences between SFP-25G-SR and SFP-25G-ESR

1). Transmission Distance

SFP-25G-SR is mainly used for short-distance transmission, while SFP-25G-ESR is suitable for longer transmission distances.

2). Fiber Type

While both can be used with OM3 and OM4 multimode fibers, the SFP-25G-ESR offers longer transmission distances when used with OM4 fiber.

3). Compatibility and Standards

SR : Complies with IEEE standards, has wide compatibility, and can be plug-and-play with mainstream switches.
ESR : This is a vendor extension solution (such as Cisco and Huawei). You must ensure that the device supports non-standard protocols.

3. Recommended Application Scenarios

SR selection scenarios:
Data center TOR (Top of Rack) connecting
servers and switches with short-distance interconnection ( ≤ 100m)
High-density deployment and cost-sensitive projects

ESR selection scenarios:
Campus network backbone links (200-300m)
Extending the life of multimode optical fibers during the renovation of old equipment rooms
requires an upgrade path compatible with 25G/100G (SR4)

4. FAQ

Q1: Can ESR replace SR?
→ Yes, but the compatibility and cost of the equipment need to be evaluated. SR is more cost-effective in short-distance scenarios.

Q2: Can OM3 fiber be used?
→ Yes, but the ESR transmission distance under OM3 will be shortened to about 200m.

Q3: What are the future upgrade suggestions?
→ If you are planning a 100G network, it is recommended to choose a module that supports SR4 (4x25G).

There are some differences between SFP-25G-SR and SFP-25G-ESR in terms of transmission distance, cost and applicable scenarios. When choosing a 25G multimode optical module, users should make comprehensive considerations based on actual network requirements, transmission distance, budget and other factors to ensure that they choose the optical module that best suits their network and achieve efficient and stable data transmission.

I hope this article can help you better understand the differences between 25G multimode optical modules. If you have any questions about the selection of optical modules or need further technical discussion, please feel free to contact us.

About ETU-Link

ETU-Link Technology Co., Ltd. was founded in 2014. It is a high-tech enterprise focusing on the research and development, production and sales of optical communication devices. With high-speed optical modules as its core products, the company professionally serves the optical fiber communication markets such as telecommunications, data communications, and storage.