Single-mode fiber optic transceiver SFP

Single-mode single-fiber SFP transceivers are hot-swappable optical modules that transmit and receive data over single-mode fiber for long-distance, high-speed network connections.

Overview

A single-mode SFP (Small Form-factor Pluggable) transceiver is an optical module designed to convert electrical signals into optical signals and vice versa, enabling network devices such as switches, routers, and servers to communicate over single-mode fiber (SMF) with minimal signal loss . Unlike multimode SFPs, which are limited to short distances, single-mode SFPs support long-distance transmission, typically ranging from 10 km to over 80 km, depending on the module type and optical power budget .

Key Specifications

• Fiber Type: Single-mode fiber with a small core diameter (~9/125 µm)
• Wavelengths: Commonly 1310 nm or 1550 nm for long-distance transmission
• Link Distance: 10 km to 70 km or more, depending on the SFP variant (e.g., 1000BASE-LX/LH up to 10 km, 1000BASE-EX up to 40 km, 1000BASE-ZX up to 70 km)
• Data Rates: Typically 1 Gbps for standard SFPs, with higher-speed variants available
• Hot-Swappable: Can be inserted or removed without powering down the network device

Single-Fiber (Bi-Directional) Operation

Some single-mode SFPs use single-fiber bi-directional (BIDI) technology, allowing both transmit and receive signals to travel over a single fiber strand. This reduces fiber cabling requirements and is ideal for retrofitting existing fiber infrastructure . BIDI SFPs use different wavelengths for transmitting and receiving, such as 1310 nm for TX and 1550 nm for RX, or vice versa.

Applications

• Campus Backbone Networks: Connecting buildings over long distances
• Metro and Telecom Networks: High-speed links between data centers or central offices
• Enterprise Networks: Uplinks and aggregation points requiring reliable long-distance connectivity
• Data Centers: Interconnecting switches and servers across large facilities

Advantages

• Long-Distance Transmission: Minimal signal attenuation over tens of kilometers
• High Bandwidth: Supports gigabit and higher speeds
• Flexibility: Hot-swappable and compatible with multiple vendors due to MSA standards
• Reduced Cabling: Single-fiber BIDI modules cut fiber usage in half

Considerations

• Compatibility: Ensure the SFP module matches the switch or router vendor and port type
• Optical Budget: Inline optical attenuators may be required for short distances to prevent receiver overload
• Wavelength Matching: TX and RX wavelengths must correspond correctly for BIDI modules Single-mode single-fiber SFP transceivers are essential for modern networks requiring long-distance, high-speed, and reliable optical connectivity, making them ideal for backbone, metro, and enterprise applications .