Walsun 400G QSFP LR4 Transceiver

About Walsun 400G QSFP-DD LR4 Optical Transceiver Module in Bangladesh

The Walsun 400G QSFP-DD LR4 is a high-speed, high-density optical transceiver designed for 400GbE data center interconnects, high-performance networking and telecom applications. It provides up to 400Gbps aggregate optical bandwidth and supports transmission distances of up to 10km over single-mode fiber.

Walsun's official product page identifies the standard 10km 400G QSFP-DD LR4 as HXEP-ML311C. The module operates at 1310nm, uses a CWDM EML transmitter and PIN receiver, supports a 425Gb/s bit rate, duplex LC connectivity, digital monitoring and a +3.3V power supply. Walsun official 400G QSFP-DD LR4 specifications

The LR4 architecture uses four optical channels to transport 400G traffic over a duplex LC single-mode fiber connection. PAM4 modulation enables approximately 100Gbps-class signaling per optical lane while maintaining the compact QSFP-DD form factor.

Walsun 400G QSFP-DD LR4 Specifications & Features

Overview

The Walsun 400G QSFP-DD LR4 is designed for next-generation high-density Ethernet infrastructure requiring 400Gbps optical connectivity across distances of up to 10km.

Its QSFP-DD form factor provides eight high-speed electrical lanes while maintaining a compact pluggable design. The module converts the electrical 400G signal into four optical channels and multiplexes them into a duplex LC single-mode fiber connection.

Walsun lists 400G QSFP-DD LR4 among its core high-speed optical products alongside 400G DR4, FR4 and other next-generation transceiver solutions. Walsun official product portfolio

Buy Walsun 400G QSFP-DD LR4 in Bangladesh

Purchase the Walsun 400G QSFP-DD LR4 Optical Transceiver Module from Datacom Technologies (BD). We supply 400G QSFP-DD optical transceivers, data center interconnect optics, high-speed Ethernet modules and enterprise/telecom networking solutions throughout Bangladesh.

Key Features

• 400Gbps high-speed optical connectivity
• Supports up to 425Gb/s bit rate
• QSFP-DD high-density form factor
• Four-channel CWDM optical architecture
• 1310nm optical wavelength
• Up to 10km SMF transmission
• Duplex LC optical interface
• CWDM EML transmitter
• PIN receiver
• PAM4 modulation
• Digital Diagnostic Monitoring
• SFF-8636 management interface
• SFF-8679 electrical interface
• +3.3V single power supply
• Hot-pluggable design
• All-metal EMI-resistant housing
• 0°C to 70°C operating temperature
• QSFP-DD Rev 4.0 compliant
• RoHS-10 compliant and lead-free

400G QSFP-DD LR4 Optical Technology

The Walsun 400G QSFP-DD LR4 uses four optical channels to transport an aggregate 400Gbps data stream. Each optical lane operates at approximately 100Gbps-class signaling using PAM4 modulation.

The four optical channels are multiplexed internally and transmitted through a duplex LC connector over single-mode fiber. At the receiving end, the optical signal is demultiplexed and converted back into electrical data.

Walsun describes 400G QSFP-DD LR4 as a high-bandwidth, long-distance optical module for 400G Ethernet and data center interconnect applications. Walsun 400G QSFP-DD LR4 technical guide

1310nm CWDM Optical Architecture

The LR4 module operates around the 1310nm optical region using four wavelength channels. CWDM technology allows the four high-speed optical signals to share a single duplex fiber pair.

This architecture reduces the number of physical fibers required compared with parallel-fiber 400G solutions such as DR4 or SR8 and enables the use of standard duplex LC connectivity.

10km Single-Mode Fiber Reach

The Walsun 400G QSFP-DD LR4 supports a maximum transmission distance of 10km over single-mode fiber.

This reach is well suited to data center interconnects, metro network connections, enterprise backbone links and high-capacity connections between geographically separated network facilities.

The actual achievable distance depends on the complete optical link budget, including fiber attenuation, connector losses, splice losses, dispersion and system margin.

PAM4 Modulation

The module uses 4-level Pulse Amplitude Modulation (PAM4) to achieve high optical bandwidth within the QSFP-DD form factor.

PAM4 carries two bits per symbol, allowing approximately 100Gbps-class signaling per optical lane while keeping the required baud rate lower than an equivalent NRZ implementation.

Walsun's technical information identifies PAM4 as the modulation technology used by its 400G QSFP-DD optical module family. Walsun 400G QSFP-DD technical information

CWDM EML Transmitter and PIN Receiver

The Walsun 400G QSFP-DD LR4 uses a CWDM EML transmitter and PIN receiver. The EML optical transmitters provide the high-speed optical signaling required for the four LR4 channels, while the PIN receivers convert the incoming optical signals back into electrical data.

Walsun's current official ordering table identifies the 10km HXEP-ML311C variant with CWDM EML transmission and PIN detection. Walsun official ordering information

Duplex LC Connectivity

The 400G QSFP-DD LR4 uses a duplex LC optical connector. One fiber carries the transmitted signal and the second fiber carries the received signal.

This makes LR4 particularly useful where existing duplex LC single-mode fiber infrastructure is available and a 400G link must be deployed without moving to MPO/MTP parallel-fiber connectivity.

Digital Diagnostic Monitoring

The module supports a digital monitoring interface through SFF-8636. Compatible host equipment can use the management interface to retrieve optical and module operating information.

Digital monitoring can help network administrators track module health, temperature, voltage, optical power and other supported operating parameters.

QSFP-DD High-Density Form Factor

QSFP-DD stands for Quad Small Form-factor Pluggable Double Density. It provides eight high-speed electrical lanes, allowing significantly higher bandwidth than traditional QSFP/QSFP28 interfaces while retaining a compact pluggable architecture.

Walsun specifies its 400G QSFP-DD LR4 as compliant with QSFP-DD Rev 4.0 and equipped with an SFF-8636 management interface and SFF-8679 general electrical interface. Walsun specifications

400G QSFP-DD LR4 vs 400G QSFP-DD DR4

LR4 is the better choice when a 400G link must travel significantly farther than a typical DR4 connection and duplex LC infrastructure is preferred.

400G QSFP-DD LR4 vs 400G QSFP-DD FR4

For links up to approximately 2km, FR4 can provide a cost-effective 400G solution. For longer links approaching 10km, LR4 is designed for the extended optical reach.

400G QSFP-DD LR4 vs 400G OSFP LR4

QSFP-DD and OSFP are different physical form factors. The correct module must match the host equipment's optical port and mechanical requirements.

Data Center & Telecom Applications

• 400GbE data center interconnect
• Data center-to-data center connectivity
• High-capacity enterprise backbone
• Metro Ethernet
• Cloud data center networks
• AI/HPC network infrastructure
• Core switch interconnection
• High-density 400GbE leaf-spine networks
• Telecom transport and aggregation
• Long-distance network equipment interconnection

Compatibility

Walsun manufactures 400G QSFP-DD modules for high-speed networking platforms and can provide customized designs and coding options. Walsun official website

Before ordering, the exact switch, router or network platform should be specified. Compatibility depends not only on the QSFP-DD physical interface but also on host firmware, optical coding, supported standards and link configuration.

Installation Considerations

• Use compatible single-mode fiber.
• Use duplex LC optical connections.
• Verify the complete 10km optical link budget.
• Check fiber attenuation and dispersion.
• Account for connector and splice losses.
• Clean and inspect LC connectors before installation.
• Verify that the host equipment supports 400G QSFP-DD LR4.
• Confirm the required OEM coding before purchase.
• Ensure both ends use compatible 400G optical specifications.

Benefits

• 400Gbps high-speed optical connectivity
• Up to 425Gb/s supported bit rate
• Up to 10km single-mode fiber reach
• 1310nm WDM architecture
• Four optical channels
• PAM4 modulation
• Duplex LC connectivity
• CWDM EML transmitter
• PIN receiver
• Digital diagnostic monitoring
• Compact QSFP-DD form factor
• Hot-pluggable design
• SFF-8636 management interface
• All-metal EMI-resistant housing

Why Buy from Datacom Technologies (BD)?

Datacom Technologies (BD) supplies Walsun 400G QSFP-DD LR4 optical transceivers, high-speed data center optics, 400G Ethernet modules, fiber networking equipment and DCI solutions in Bangladesh. Customers can receive competitive pricing, technical consultation, compatibility guidance and nationwide delivery.

• Call/WhatsApp: +8801748173213
• Email: sales@datacomtechbd.com
• Alternative Email: datacomtechnologiesbd@gmail.com
• Office: Tropical Center, 218, Dr. Kudroti Khuda Road, New Elephant Road, Dhaka-1205, Bangladesh

Frequently Asked Questions (FAQ)

Q1: What is the Walsun 400G QSFP-DD LR4?
It is a 400Gbps QSFP-DD optical transceiver designed for up to 10km single-mode fiber transmission using a four-channel WDM architecture.

Q2: What is the Walsun part number?
The official Walsun ordering table identifies the standard 10km LR4 variant as HXEP-ML311C.

Q3: What is the maximum transmission distance?
The standard LR4 variant supports up to 10km over single-mode fiber.

Q4: What wavelength does it use?
The LR4 operates around the 1310nm optical window using four WDM channels.

Q5: What fiber does it require?
It requires compatible single-mode fiber.

Q6: What connector does it use?
It uses a duplex LC optical connector.

Q7: Does the module use PAM4?
Yes. Walsun's 400G QSFP-DD LR4 architecture uses PAM4 signaling.

Q8: What transmitter and receiver does it use?
The standard 10km HXEP-ML311C uses a CWDM EML transmitter and PIN receiver.

Q9: Does it support DDM?
Yes. The module supports digital monitoring through an SFF-8636 management interface.

Q10: Is QSFP-DD the same as QSFP+?
No. QSFP-DD is a newer double-density form factor with eight electrical lanes designed for much higher data rates such as 200G and 400G.

Q11: Is 400G QSFP-DD LR4 compatible with 400G OSFP?
No. QSFP-DD and OSFP are different physical form factors. The module must match the host equipment's port type.

Q12: Where can I buy Walsun 400G QSFP-DD LR4 in Bangladesh?
You can contact Datacom Technologies (BD) for Walsun 400G QSFP-DD LR4 optical transceivers, 400G data center optics and high-speed networking solutions with nationwide delivery.