An Overview of Long-Distance Optical Transceiver: Definition, Types and Application Cautions

With the development of network tech, the long-distance optical transceiver module is in great favor of users who need long-reach data transmission in the optical communication industry. Maybe many people are using the optical module, but having little knowledge of it, such as its definition, its types and its application cautions, etc. Today, Gigalight will have an introduction to it in this article.

The Definition of Long-Distance Optical Transceiver

Transmission distance is regarded as one of the key factors of the optical module. The optical transceiver is divided into short distance optics, middle distance optics, and long distance optics. The transmission distance of long-distance optical transceiver is over 30kms, but it cannot reach the maximum distance in the many situations at the process of its actual application. It is due to that the dispersion appears when an optical signal transmitting in the optic fiber. To solve this problem, long-distance optical transceiver takes the DFB laser only with one main wavelength as the light source. After that, the dispersion can be avoided.

Types of Long-Distance Optical Transceiver

Among these optical transceivers such as SFP optics, SFP+ optics, XFP optics, 40G QSFP+ optics, and 100G QSFP28 optical transceiver, there exist some long-distance optical transceiver modules. Thereinto, long-distance SFP+ optical transceiver adopts EML laser components and optical photodetector components, which reduces the power consumption and raises the accuracy via improvements in many aspects. 40G long-distance optical module adopts driver and modulation unit in the transmitting link, the transmission distance is far more than that of the existing standard 40G pluggable optical module.

  • Applications of Long-Distance Optical Transceiver
  • For the interface of the switcher
  • For the interface of the server
  • For the interface of network card
  • In the security, monitoring filed
  • In the telecom field, including a data control center and computer room, etc.
  • Ethernet, Fiber Channel(FC), Synchronous Digital Hierarchy (SDH), etc.

Cautions for the Utilization of Long Distance Optics

The long-distance optical transceiver has higher requirements for the range of receiving optical power. If the optical power exceeds the range of receiving sensitivity, the failure of the optical transceiver module will happen. The use of tips and cautions are as follows:

  1. After the installation of the long-distance optical module into the device, patch cord cannot be connected at once. Using the instruction” display transceiver diagnosis interface” to read the transmitting and receiving an optical power of the optical transceiver module, checking whether the optical power is in the normal range.
  2. If the condition is allowable, the optical power meter can be used to test the optics. After the transmitting and receiving optical power is at the normal range, the optic fiber can be connected into long distance optical transceiver.
  3. In any case, the optic fiber module cannot be used to test the long-distance optical module. If it is necessary, it must be connected with the optical attenuator to make the receiving optical power within the normal receiving range. After that, the loopback test can be operated.
  4. Using the long-distance optical module, the receiving optical power must keep some margins. Besides, the actual receiving optical power is reserved at over 3dB compared with the receiving sensitivity. If it can not be achieved, the attenuator needs to be used.
  5. Long distance optical module can be used completely without attenuation in the 10km transmission application. Generally speaking, an optical module over 40km will need to be added attention. It can not be directly connected, or the ROSA is easily burnt.


Above is the introduction to the definition of a long-distance optical module, types of long-distance optical module, and application cautions of the long-distance optical module. Generally speaking, long-distance optical module satisfies most users’ requirements for transmission distance to a large degree. It is believed that long-distance optical module can further meet market demands on performance, power consumption, cost and so on, with the network techs constantly improved. More details are at Gigalight.

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