2017-12-12

Types and Standards of 100G Optical Transceivers

As people demand higher and higher bandwidth, 100G networks has been developed rapidly. 100G optical module is an important part of 100G network. Now, there are several important standards and types of 100G optical transceivers. This post will introduce the related knowledge of 100G optical module in detail.

Types of 100G Optical Transceivers


The form factors of 100G optical transceivers mainly include: CFP, CFP2, CFP4 and QSFP28. To compare their advantages, the main factor to consider is the data center costs and power consumption.

1. CFP optical transceiver supports all C-band wavelengths tunable. It is able to complete the link detection by using a common optical dual binary modulation format ODB. The power consumption is less than 24W.

2. The volume of CFP2 optical module is one-half the CFP, whose integration is 2 times of CFP. It can complete the wide dynamic input range based on SOA to achieve stable admission sensitivity. It supports a full CFP optical module and its low power consumption is lower than 9W.

3. The volume of CFP4 optical transceiver is one-half the CFP2’s, its integration is twice that of CFP2. The front panel port density is also doubled compared with CFP2. CFP4 optical module MSA protocol supports the same rate of CFP2 and CFP2s. The transmission power has increased significantly, but the power consumption has dropped significantly, only about half of the original, the system cost is lower than the CFP2. In addition, CFP4 optical module select 4 * 25 form, through the 425G channel to complete 100G transmission, higher transmission power, more stable.

4. QSFP28 optical transceiver module form factor style is smaller than the CFP4 optical module. QSFP28 optical module power consumption is generally not more than 3.5W; the use of QSFP28 optical module can directly upgrade through the 40G to 100G, the cost is lower. There are all kinds of 100G QSFP28 optical transceivers in the market, like QSFP28 100GBASE-CWDM4, QSFP28 100GBASE-PSM4, QSFP28 100GBASE-SR4, and QSFP28 100GBASE-LR4, etc.



100G Optical Transceiver Standard


Since the coming of 100G networks, IEEE, Multi-SAource Agreement (MSA) industry alliances and other agencies have formulated a number of standards for 100G optical modules. Among the many standards, the PSM4 and CWDM4 standards are developed by the Multi-Source Agreement (MSA) industry group, which are more suitable for the mainstream 100G QSFP28 optical modules on the market today. The following table is the specific circumstances of some common 100G optical transceiver standard:


Note:

The 100G PSM4 standard is introduced primarily to reduce the cost of expensive 100GBASE-LR4 optical modules. The 100G PSM4 optical transceiver is a single-mode, parallel, four-channel optical module designed for applications in the data center of 500 meters.

The 100G CWDM4 standard is mainly formulated for the deployment of a 2km 100G link in a data center. The interface of a 100G CWDM4 optical transceiver conforms to the 2km 100G optical interface specification of duplex single mode optical fiber, and the transmission distance can reach 2km.