PRIMUS IT Limited.
PRIMUS IT Limited.

Types and Applications of SFP Optical Modules

SFP optical module is a hot-swappable small package module in SFP package, the maximum rate can reach 10.3G, and the interface is LC. SFP optical modules are mainly composed of lasers. SFP classification can be divided into rate classification, wavelength classification, and mode classification. So, what is SFP? What are the types and applications of SFP optical modules? Let's take a look together next.

Ⅰ. What is an SFP optical module?

SFP, short for Small Form-Factor Pluggable, is a compact, hot-swappable optical module used in telecom and datacom applications. The SFP optical module can be considered as an upgraded version of the GBIC optical module. Unlike GBIC with SC fiber interface, SFP has LC interface, and the body size is only about half of GBIC, making SFP more space-saving. SFP connects the motherboard of a network device (such as a router, switch, media converter, or similar device) to a fiber optic cable or cable. At the same time, SFP is a common industrial specification supported by many network device suppliers. It was designed to support SONET, Gigabit Ethernet, Fibre Channel and other communication standards.

Ⅱ. Standardization of SFP optical modules

1. SFP optical modules are not regulated by any official standard system, but are regulated by the Multilateral Agreement (MSA) between competing manufacturers. SFP is designed according to the GBIC interface and achieves a greater port density (the number of optical modules per centimeter along the edge of the motherboard) than GBIC, which is why SFP is also called mini-GBIC. A related small-package optical module has a similar size to an SFP, but it is soldered to the motherboard as a type of pin, rather than plugged into an edge card slot.

2. However, in practical applications, some network equipment manufacturers use a key mechanism to break compatibility with "universal" SFPs, that is, add a verification process to the device firmware so that the device only enables the vendor's own optical modules .

Ⅲ. Types of SFP Optical Modules

1. SFP optical modules are sold in the market with a variety of transmitter and receiver types, allowing users to choose the appropriate optical module for each link to achieve the available fiber types (such as: multimode fiber or single mode fiber) light transmission on.

2. On the market, there are usually several different types of SFP optical modules:

(1) Multimode fiber with black or beige connectors;

(2) Single-mode fiber with blue connector;

(3) Copper twisted pair wiring system

1000BASE-T – These optical modules have very important interface circuits inside and can only be used for Gigabit Ethernet because that is the interface they implement. They are not compatible with Fibre Channel or SONET (more precisely, there is no equivalent interface).

(4) WDM (wavelength division multiplexing) system

Single fiber bidirectional SFP for bidirectional transmission on one fiber. These optical modules with CWDM (Coarse Wavelength Division Multiplexing) double the transmission density on fiber optic links.

CWDM (Coarse Wavelength Division Multiplexing) and DWDM (Dense Wavelength Division Multiplexing) optical modules achieve multiple maximum distances on multiple wavelengths.

Ⅳ. The application of SFP optical module

There are multi-mode fiber SFP optical modules and single-mode fiber SFP optical modules on the market, allowing users to select the appropriate optical module for each link to achieve optical transmission on the available fiber types. In addition, there are electrical SFP optical modules, which allow host devices designed for optical fiber communications to communicate over unshielded twisted-pair network cables. The new SFP optical modules support the DDM (Digital Diagnostic Monitoring) function, also known as DOM (Digital Optical Monitoring). This feature enables users to monitor real-time parameters of SFP optical modules such as: optical output power, optical input power, temperature, laser bias current, and optical module supply voltage.