How are Optical Transceivers Classified?

Optical transceivers as optical devices to complete the photoelectric conversion, essential in optical communication networks, common gigabit/ 10 Gigabit optical transceivers, SFP/ SFP+/ QSFP28 optical transceivers, etc., then do you know how these optical transceivers are classified? What other types are there? Next I will introduce in this article.

Classification of Optical Transceivers

In order to meet the needs of different applications, optical transceivers with different parameters and functions have come into being. The classification methods and types of optical transceivers are detailed as follows.

Package Form

Optical transceivers are divided into the following common types according to package form: SFP, SFP+, SFP28, QSFP+, QSFP28, and QSFP-DD.

SFP optical transceiver is an upgraded version of GBIC with a maximum rate of 4.25G, mainly consisting of lasers, and is characterized by being small and hot-swappable.

The SFP+ optical transceiver is an enhanced version of the SFP with a transmission rate of 10Gbps, which can meet 8.5G Fibre Channel and 10G Ethernet applications.

The SFP28 optical transceiver has a transmission rate of 25Gbps, which has the advantages of lower power consumption, higher port density, and support for hot-swappable.

The QSFP+ optical transceiver has a transmission rate of 40Gbps, supports MPO fiber connectors and LC fiber connectors, and is characterized by being small and hot-swappable.

The QSFP28 optical transceiver uses four 25Gbit/s channels for parallel transmission with a transmission rate of 100Gbps to meet 100G Ethernet applications.

QSFP-DD optical transceivers are available in 200Gbps and 400Gbps rates with eight 25Gbit/s channels and eight 50Gbit/s channels, respectively.

Transmission Rate

The transmission rate of optical transceivers refers to the number of bits of data transmitted per second (bit), and the unit is Mb/s and Gb/s. The transmission rate usually ranges from 100 Mb/s to 400 Gb/s, and the common transmission rates are 1 Gb/s, 10 Gb/s, 25 Gb/s, 40 Gb/s, 100 Gb/s and 400 Gb/s. According to the different transmission rates, optical transceivers can be divided into 1G optical transceiver (i.e. Gigabit optical transceiver), 10G optical transceiver (i.e. 10 Gigabit optical transceiver), 25 optical transceiver, 40G optical transceiver, 100G optical transceiver and 400G optical transceiver, etc.

Transmission Distance

According to the transmission distance, the optical transceiver can be divided into short distance, medium distance and long distance. The transmission distance of short distance optical transceiver is 2km and below, the transmission distance of medium distance optical transceiver is between 10~20km, and the transmission distance of long distance optical transceiver is more than 30km.

Transmission Mode

Optical transceivers can be divided into simplex optical transceivers, half-duplex optical transceivers and full-duplex optical transceivers according to the supported data transmission methods. Simplex optical transceivers only support data transmission in the same direction, such as TV stations can send signals to viewers, but viewers cannot send signals to TV stations; half-duplex optical transceivers support data transmission in two directions, but do not support data transmission in two directions at the same time, such as walkie-talkies can support talking to each other, but do not support talking at the same time; full-duplex optical transceivers support data transmission in two directions at the same time such as cell phone can support both sides to talk at the same time.

Central Wavelength

The working wavelength of optical transceiver is a range, but we are generally used to use the center wavelength to describe instead of the working wavelength. Depending on the center wavelength, optical transceivers can be divided into common optical transceivers and color optical transceivers. The center wavelength of common optical transceiver is 850nm, 1310nm and 1550nm, while the center wavelength of color optical transceiver is CWDM wavelength and DWDM wavelength, where CWDM wavelength range is 1270~1610nm and DWDM wavelength range is 1525~1565nm or 1570~1610nm, the color optical transceiver with CWDM wavelength are called coarse wavelength optical transceivers, and color optical transceivers with DWDM wavelengths are called dense wavelength optical transceivers.

Fiber Types

Optical transceivers can be divided into single-mode optical transceivers and multimode optical transceivers according to the applicable fiber type, where single-mode and multimode refer to the transmission mode of the fiber in the optical transceiver. Single-mode optical transceivers are mostly used in long-distance transmission, while multimode optical transceivers are mostly used in short-distance transmission.

Interface Types

There are two types of optical transceiver interfaces, fiber optic interface and RJ45 interface. Fiber optic interface is generally used to connect fiber optic patch cable with LC, MTP/MPO connectors, etc. Optical transceivers with this kind of interface are usually called optical port transceivers; while RJ45 interface as the name implies is the interface used to connect network cables, we generally call optical transceivers with this kind of interface electrical port transceivers. In short, the main difference between the electrical and optical transceivers is the difference in transmission medium, the electrical transceiver transmits the electrical signal, the optical transceiver transmits the optical signal.

Operating Temperature

Optical transceivers are mainly classified into commercial-grade optical transceivers and industrial-grade optical transceivers according to different working temperatures, where the working temperature of commercial-grade optical transceivers is between 0℃~70℃ and the working temperature of industrial optical transceivers is between -40℃~85℃.

Manufacturers

Optical transceivers can be divided into original optical transceivers or compatible optical transceivers according to the manufacturer of optical transceivers. Original optical transceivers refer to optical transceivers made by original equipment manufacturers, such as Cisco, Huawei and H3C brands of optical transceivers, which are more expensive compared to compatible optical transceivers. Compatible optical transceivers refer to optical transceivers made by third-party manufacturers, which can be adapted to the original equipment, such as Cisco, Huawei, H3C and other brands of switches, and lower cost than original optical transceivers, and also provide a lifetime warranty, but the disadvantage is that their quality is uneven.

Application Areas

According to the different application fields, optical transceivers can be divided into SDH optical transceivers, Fibre Channel optical transceivers, Ethernet optical transceivers and digital video optical transceivers.
SDH optical transceivers are mainly used in SDH/SONET networks, such as common Gigabit SFP optical transceivers, 10 Gigabit SFP+ optical transceivers, etc.
Fibre Channel optical transceivers are mainly used in Fibre Channel storage network links in data centers, featuring miniaturization, low power consumption and hot swapping, which can meet the demand of fast transmission of large amount of information.
Ethernet optical transceivers are mainly used in LANs, such as common common optical transceivers, WDM optical transceivers and BiDi optical transceivers, etc.
Digital video optical transceivers are mainly used in PDH optical terminals and HD video transmission, and are characterized by small size and hot-swappable.

Summary

Based on the above, we can see that different application environments require different types of optical transceivers. When purchasing optical transceivers, we need to fully understand the application environment and the usage of different optical transceivers, and then choose the most suitable optical transceiver by combining the actual wiring requirements.