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How to Choose an Optical Module

When it comes to optical modules, there are a lot of different factors that you need to take into account. The type of module, the wavelength range, the output power – all of these things matter when you’re trying to find the perfect module for your device. In this blog post, we’ll walk you through the process of choosing an optical module and help you figure out which one is right for your needs. Optical modules are the core accessories of optical fiber communication. Nowadays, there are many varieties of optical modules on the market. What factors should we consider when purchasing optical modules? How can I purchase a suitable optical module? Factors to consider when purchasing optical modules.

Speed and Form Factor

(1) SFP: for 155M, 1.25G, 2.5G, 6G optical modules

(2) SFP+: the mainstream package of 10G optical modules

(3) SFP28: Form factor of 25G optical module

(4) QSFP+: Form factor of 40G optical module

(5) QSFP28: Form factor of 100G optical module

When selecting an optical module, the relevant master device will clearly lock the supported optical module package and rate.

Transmission Distance

The transmission distance of optical modules is divided into three types: short distance, medium distance and long distance. Usually, short distance transmission refers to the transmission distance below 2km, and the medium distance is 10-20km. ≥30km is long-distance transmission such as common 40km, 80km, 120km, etc. We can choose an optical module with a suitable transmission distance according to an actual use situation. In addition, it should be noted that the transmission distance of the optical module we choose should be slightly larger than the transmission distance of the actual application, so as to ensure the transmission quality.

Transmission Method

Optical modules can be divided into single-fiber optical modules and dual-fiber optical modules according to the transmission mode. The single-fiber optical module has only one optical fiber interface, and one optical fiber transmits and receives optical signals at the same time; the dual-fiber optical module has two optical fiber interfaces, which connect two optical fibers, and transmit and receive one optical fiber each. When selecting an optical module, it should be noted that if the opposite optical module is a single-fiber or dual-fiber module, only the same one can be connected.


Common optical modules include LC interface, SC interface and MPO interface. The electrical interface module uses RJ45 interface. To realize information exchange between optical modules, the two optical modules must be connected. When selecting optical modules, pay attention to and connect. The jumper connectors must match to be inserted for transmission.


Common optical module wavelengths are 850nm, 1310nm, 1550nm, CWDM, DWDM, etc. It should be noted that in the dual-fiber transmission mode, the wavelengths of the two interconnected optical modules must be the same. Single-fiber optical modules need to be used in pairs. For example, the wavelength of one end is: TX1310/RX1550nm (TX is the transmit wavelength, RX is the receive wavelength), then the opposite end must select an optical module with a transmit and receive wavelength of TX1550/RX1310nm.

Working Temperature

Optical modules can be divided into:

(1) Commercial temperature (0-70°C): used in data centers and enterprise computer rooms. Because air conditioners are installed in data centers and computer rooms to maintain room temperature.

(2) Extended temperature (-20-85°C): If you use outdoor nodes in tropical areas, you can consider extended temperature modules.

(3) Industrial-grade temperature (-40-85℃): used in environments with large temperature changes such as outdoors, remote mountainous areas, tunnels, etc., industrial-grade optical modules will import temperature compensation software, which is used to ensure the stability of the optical module. When the temperature changes, the temperature compensation software will take effect.

The optical module is greatly affected by the temperature during operation. If the operating temperature of the optical module is too high or too low, the optical power will generally decrease, the sensitivity will become lower, and the eye pattern will become worse. In severe cases, the communication data will be lost. Errors may even cause the optical module to be scrapped, so it is necessary to select an optical module with an appropriate temperature level according to the actual use environment.


Equipment manufacturers of optical modules will encrypt their equipment to varying degrees, which is what we call compatibility. Modules of your own brand can only be used on your own equipment, and optical modules of other brands cannot be matched with your own equipment. Compatibility manufacturers need to perform different compatibility adaptations on optical modules, and it is particularly important to be able to perfectly solve the adaptation problem.


Nowadays, more and more suppliers have limited selection of compatible optical modules, whose quality is completely comparable to the original optical modules, but the price is very competitive, which can help save a lot of costs.

Quality and Service

If there is a problem with the optical module in the first 1-2 years of use, it can be judged that it is a quality problem of the optical module. Therefore, we must choose a trustworthy optical module manufacturer when purchasing compatible optical modules.

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