QSFP28 CWDM4 Optical Transceiver Overview

Updated on Jul 20, 2022


100G QSFP28 Transceivers

Currently, the QSFP28 is considered as the primary form factor for 100G Ethernet in enterprise networks and data centers. But how much do you know about them? In the previous post, the QSFP28 SR4, QSFP28 LR4, and QSFP28 PSM4 have been narrated in detail. Here, we are going to talk about the QSFP28 CWDM4 optical transceiver through the perspectives of definition, working principle, specifications, applications, and FAQs.


What Is 100G QSFP28 CWDM4?

The QSFP28 100G CWDM4 is a hot-pluggable, full-duplex, and photonic-integrated optical transceiver designed to comply with the QSFP MSA, CWDM4 MSA, and portions of IEEE P802.3bm standard. It features with LC duplex connectors, which can provide a high-speed 100Gbps transmission with a maximum distance of 2km on SMF. More specifically, the QSFP 100G CWDM4 module adopts WDM technology that enables four wavelengths to be multiplexed to transmit on a single fiber, which greatly saves optical fiber resources. The maximum transmission distance of QSFP28 LR4 is 10km which includes the transmission distance of the 100G QSFP28 CWDM4 module. So why don’t we use the QSFP 100G LR4 to transmit 2km directly? The reason is that the QSFP28 LR4 transceiver has a higher consumption and higher laser cost than QSFP 100G CWDM4. Thus the 100G CWDM4 modules make up for the drawback that the cost for QSFP 100G LR4 transmitting 2km is too high.


How Does QSFP28 CWDM4 Work?

The QSFP28 CWDM4 optical transceiver module converts four input wavelengths of 25Gb/s electrical data to four channels of CWDM optical signals and then multiplexes them into a single channel for 100Gb/s optical transmission. On the other end, the QSFP 100G CWDM4 de-multiplexes a 100Gb/s optical input into four channels of CWDM optical signals and then converts them to four output channels of electrical data on the receiver side.

QSFP28 CWDM4 Working Principle.jpg

Figure 1: QSFP28 CWDM4 Module Working Principle


FS QSFP28 CWDM4 Datasheet

All FS QSFP 100G CWDM4 optical transceivers are manufactured to satisfy the industry standard and have been recognized by numerous customers. They are proven to be compatible with over 200 vendors, such as Cisco, Juniper, Arista, Brocade, Dell, and so on.

QSFP 100G CWDM4 Specification

Form Type QSFP28
Wavelength 1271nm, 1291nm, 1311nm, 1331nm
Connector LC Duplex
Cable Type SMF
TX Power ~-6.5-2.5dBm
Protocols 100G Ethernet, MSA Compliant
Max Data Rate 103.1 Gbps
Max Cable Distance 2km
Transmitter Type DML CWDM
DDM/DOM Supported
Receiver Sensitivity <-11.5dBm
Commercial Temperature Range 0℃ to 70℃ (32 to 158°F)

QSFP 100G CWDM4 Benefits

  • All FS QSFP28 CWDM4 modules must run through programming and an extensive series of platform diagnostic tests to ensure their performance and compatibility. And FS 100GBASE-CWDM4 optical modules are fully interoperable with non-FS 100G CWDM4 transceivers as long as they meet the associated industry standard specifications.

  • All QSFP 100G CWDM4 transceivers from FS are provided with exchange service within a year and five-year warranty.

  • FS 100G QSFP28 CWDM4 modules can be reconfigured for any network hardware at a moment’s notice with the help of the transceiver coding tool - FS Box. In this way, the QSFP 100G CWDM4 modules are programmed on-site to be compatible with over 200 OEM devices efficiently and flexibly.

  • With large stock in our US, AU, GE, SG warehouse, QSFP28 CWDM4 100G modules can be shipped the same day after ordering.

QSFP 100G CWDM4 Cabling and Connectivity

The QSFP 100G CWDM4 adopts WDM technology to transmit signals with a maximum transmission distance of 2km on a single fiber, greatly saving optical fiber resources. In most cases, QSFP28 CWDM4 transceivers can be used for 100G to 100G interconnection in enterprise networks and data centers.

100G-100G Interconnect Cabling Solution with Fiber Adapter Panel

The method to connect with the FHD fiber adapter panel is very straightforward. As the following diagram shows, two QSFP28 CWDM4 modules are plugged into two 100G switches. And the 100G to 100G interconnection can be achieved by using FHD fiber patch panel, rack mount fiber enclosure, and LC duplex single-mode fiber patch cable. In this solution, the fiber enclosure and adapter panels are used for structured cable management.

QSFP28 CWDM4 100G-100G Interconnect Cabling.jpg

Figure 2: QSFP28 CWDM4 Module 100G to 100G Interconnection



Q1: Is FEC required to be turned on to operate a pair of the 100G QSFP28 CWDM4 optics?

A: When using the QSFP28 CWDM4 modules, both ends need to open or close the FEC at the same time (the FEC function is turned on to reduce the bit error rate).

Q2: What is the main difference between QSFP 100G CWDM4 and 100G CLR4 Modules?

A: The main difference is the Forward Error Correction (FEC) function. For QSFP 100G CWDM4, it is required for supporting FEC. As for the 100G CLR4, the FEC is an optional function. It can support operation with and without FEC. The 100G CLR4 can enable FEC function for increasing link margin or maintain the performance of low latency and low power without FEC function.

Q3: How QSFP28 CWDM4 Differs from the QSFP 100G PSM4 module?

A: The QSFP28 CWDM4 and QSFP 100G PSM4 both can be transmitted on four wavelengths. But the QSFP28 PSM4 uses four independent wavelengths to transmit signals via 8-fiber MTP/MPO single-mode fiber patch cables. While the QSFP 100G CWDM4 enables four wavelengths to be multiplexed to transmit on a single fiber, the transmission can be achieved by just 2-fibers LC duplex single-mode fiber patch cables.

Q4: What is the power consumption of the QSFP 100G CWDM4 module?

A: The maximum power consumption of QSFP28 CWDM4 is 3.5W. All FS 100G QSFP switch ports are designed to handle QSFP 100G transceivers that draw up to 4.5W. If a 100G QSFP28 CWDM4 draws greater than 4.5W, FS cannot guarantee the performance since there are other dependencies like airflow direction, ambient temperature, elevation, etc.

Q5: Is it necessary to clean the connector of the QSFP28 CWDM4?

A: Yes, it is highly recommended that a data center facility implement cleaning procedures for all fiber optic connectors to reduce link failures and unnecessary replacement of expensive and critical network equipment.

Q6: Will using compatible QSFP 100G CWDM4 optics in my equipment negatively affect my manufacturer’s warranty?

A: No. Network equipment manufacturers do not require that you use only name-brand optics. In fact, when a product fault or defect occurs in the network, and the fault or defect is not attributable to the use of third-party optics, they will continue to provide support for the affected product under warranty or covered by their support program.

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