What Is an SFP Module?
An SFP (Small Form-factor Pluggable) module is a hot-pluggable transceiver used to connect fiber optic or copper cables to network devices such as switches, routers, and servers. It converts electrical signals into optical signals for data transmission over fiber.
SFP modules are widely used in enterprise networks, data centers, telecom networks, and FTTH access networks. Langzhi Technology offers a range of SFP modules including GPON/EPON OLT Class C+ transceivers compatible with Huawei, ZTE, and other major brands.
SFP Module Types
By Data Rate
- SFP (1G) — Gigabit, the most basic SFP module
- SFP+ (10G) — 10 Gigabit, ideal for data center core links
- SFP28 (25G) — 25 Gigabit, next-gen data center solution
By Transmission Medium
- Fiber SFP — Optical transmission via fiber cable (SMF or MMF)
- Copper SFP (RJ45) — Converts SFP slot to standard Ethernet port
- DAC Cable — Direct Attach Copper for short in-rack connections (<7m)
By Fiber Type
- Single-mode SFP (SMF) — 9μm core, 1310nm/1550nm, long distance (10-120km)
- Multimode SFP (MMF) — 50/62.5μm core, 850nm, short distance (<550m), lower cost
How to Choose the Right SFP Module
Step 1: Check Device Compatibility
Identify your switch/router port type: SFP (1G), SFP+ (10G), or SFP28 (25G). Note: SFP+ modules cannot be inserted into SFP ports. Check brand compatibility — some brands like Cisco require vendor-coded third-party modules.
Step 2: Determine Speed Requirements
Access layer: 1G SFP | Aggregation layer: 10G SFP+ | Core layer: 25G/40G modules
Step 3: Choose Transmission Distance
- SR (Short Reach) — ≤300m, multimode, lowest cost
- LR (Long Reach) — 10km, single-mode, most common specification
- ER (Extended Reach) — 40km, single-mode
- ZR (Very Long Reach) — 80-120km, single-mode
Step 4: Match Fiber Type
Single-mode modules must use single-mode fiber; multimode modules must use multimode fiber. Never mix them. Yellow cable = SMF, Aqua/Orange = MMF.
Step 5: Confirm Wavelength
Both link ends must use the same wavelength: 850nm=MMF short range, 1310nm=SMF standard, 1550nm=SMF long range. BiDi modules use different wavelengths for bidirectional transmission over one fiber.
Frequently Asked Questions
Can SFP and SFP+ be mixed?
SFP modules can work in SFP+ ports (running at 1G), but SFP+ modules cannot work in SFP ports.
Are third-party compatible modules reliable?
Yes, if the supplier provides proper EEPROM coding and real-device testing, third-party modules perform identically to OEM modules at a fraction of the cost.
Can single-mode and multimode modules connect?
No. Wavelength and fiber type mismatch will cause link failure.
Conclusion
Key steps to choose the right SFP module: check device compatibility first, then match speed, distance, fiber type, and wavelength. Langzhi Technology offers quality-tested SFP modules compatible with Huawei, ZTE, Cisco, and more.
