PRIMUS IT Limited.
PRIMUS IT Limited.

Classification of Optical Modules. How to Choose an Optical Module?

The optical module is composed of optoelectronic devices, functional circuits and optical interfaces. The optoelectronic device includes two parts: transmitting and receiving. Simply put, the role of the optical module is photoelectric conversion. The transmitting end converts the electrical signal into an optical signal, and after transmitting it through the optical fiber, the receiving end converts the optical signal into an electrical signal. Common names are: optical module, optical fiber module, optical receiving and transmitting integrated module. The following is a detailed classification of optical modules provided by Shenzhen PRIMUS IT Limited.

Ⅰ. Classification of the optical module:

There are many fiber module types. Optical modules are classified according to packaging form and speed. Common categories are SFP, SFP+, XFP, QSFP+, CFP, GBIC, CXP, X2, Xenpak, CFP2, CFP4, DAC, AOC, etc.

1. At present, the most commonly used optical modules are:

(1) SFP optical module: The transmission rate is 100M and Gigabit. Common rates are 155Mb/s, 622Mb/s, 1.25Gb/s, 2.5Gb/s, 3Gb/s.

(2) SFP+ optical module: The transmission rate is 10 Gigabit, that is, 10Gb/s.

(3) QSFP+ optical module: the transmission rate is 40G and 100G.

(4) CFP, CFP2, CFP4 optical modules: transmission rates are mainly 40G and 100G.

(5) DAC high-speed cable: The cable is made of copper, and the transmission rate is 10G, 40G and 100G.

(6) AOC high-speed optical cable: The transmission medium is optical fiber, and the transmission rate is 10G, 40G and 100G.

Ⅱ. How to choose an optical module?

When choosing an optical fiber module, the following 4 points are the key considerations:

1. Transmission distance of optical module: The transmission distance supported by different optical modules is different. Generally speaking, the transmission distance of a multi-mode optical module is much shorter than that of a single-mode optical module, and the price is cheaper. For example, the transmission distance of a 10GBASE-SR SFP+ optical module can only reach 400m, while the transmission distance of a 10GBASE-LR SFP+ optical module can reach 10km. Therefore, it is very important to figure out the transmission distance you want to reach. In addition, considering the attenuation and diffusion of optical signals during transmission, it is recommended that you use optical modules that support transmission distances slightly greater than actual requirements. For short-distance connections between devices in the rack, it is recommended that you use high-speed cable products that are cheaper than optical modules.

2. Optical module transmission mode: There are three main data transmission modes for optical modules: simplex, half-duplex and full-duplex. Simplex transmission only supports data transmission in one direction; half-duplex transmission allows data transmission in two directions, but only allows data transmission in one direction at a time; full-duplex transmission allows data transmission in both directions Simultaneous transmission. It is better to choose an optical module that supports full-duplex transmission.

3. Optical module transmission media: Copper cables and optical cables are two of the most widely used transmission media at present. Therefore, some optical modules are of electrical port design, and some optical modules are of optical port design. Generally speaking, optical port optical modules are commonly used in 10G and 40G Ethernet transmission applications, while electrical port optical modules are used in 100M and Gigabit Ethernet applications. Moreover, the transmission distance of the optical port optical module is generally longer than that of the electrical port optical module.

4. The heat resistance of the optical module: The working environment temperature of the optical module should not be too high. If it exceeds the temperature that the optical module can withstand, link failure is likely to occur. Therefore, optical modules with good heat resistance should be selected.