QSFP-40G-LM4 Dell Multi Mode Fibre 1270nm to 1330nm 40 Gigabit QSFP+ Transceiver Module

Comprehensive Product Overview

The Dell QSFP-40G-LM4 is a 40 Gigabit Ethernet hot‑pluggable QSFP+ transceiver designed for enterprise data centers, high‑performance computing clusters, and top‑of‑rack switching environments. Operating over duplex multimode fibre (MMF) with an uncooled CWDM grid (1270nm, 1290nm, 1310nm, 1330nm), this module delivers 40 Gbps reach up to 150 meters on OM3/OM4 multimode fibre.

Main Specifications

• Manufacturer: Dell
• Part Number: QSFP-40G-LM4
• Product Type: QSFP+ Optical Transceiver Module

Technical Highlights

• Supports blazing-fast 40Gb/s data transfer
• Engineered for 40GBase-LM4 connectivity
• Optimized for multi-mode fiber applications
• Wavelength range: 1270nm – 1330nm
• Reliable duplex LC interface
• Designed for consistent signal integrity

Interface Type

• QSFP+ form factor for enterprise networking
• Duplex LC connector ensuring secure fit
• Streamlined integration with Dell systems

Deployment Benefits

• Ideal for data center scalability
• Supports high-bandwidth aggregation
• Ensures low-latency communication

Key Advantages

• Stable transmission across supported wavelengths
• Durable design for long-term usage
• Engineered for enterprise-grade workloads

Use Cases

• High-speed backbone connectivity
• Cloud infrastructure expansion
• Large-scale server interconnects

Dell QSFP-40G-LM4 40 Gigabit QSFP+ Transceiver

The Dell QSFP-40G-LM4 40 Gigabit Multi Mode Fibre transceiver module is a high-performance optical networking component engineered to support ultra-fast data transmission across enterprise, hyperscale, and data center infrastructures. Designed for 40GbE environments, this QSFP+ transceiver operates across four optical lanes using wavelength multiplexing technology that ranges from 1270nm to 1330nm, enabling reliable parallel optical communication over multimode fiber links. The module is optimized for short-range transmission up to 150 meters and integrates advanced digital diagnostics monitoring functions to ensure real-time visibility into performance metrics such as temperature, voltage, optical output power, and receiver sensitivity.

Optical Architecture and Wavelength Multiplexing Technology

The Dell QSFP-40G-LM4 module uses four distinct optical wavelengths transmitted simultaneously across a duplex multimode fiber pair. Each wavelength carries a separate data stream, and the combined throughput results in a full 40Gbps aggregated bandwidth. The wavelength range of 1270nm to 1330nm enables efficient optical channel separation while minimizing interference and attenuation, which ensures signal integrity even in dense cabling environments. The optical multiplexing architecture allows the module to convert four independent electrical lanes into four optical lanes and then recombine them on reception, providing efficient parallel transmission without requiring additional fiber infrastructure.

Data Encoding

Each of the four internal transmission lanes operates at 10Gbps using high-speed modulation and encoding techniques designed for minimal latency and error rates. The internal serializer/deserializer circuitry converts host interface electrical signals into optical signals for transmission through the multimode fiber. On the receiving end, photodiodes capture incoming optical signals and convert them back into electrical data streams that are reconstructed into a unified 40Gbps output. This lane architecture ensures balanced load distribution, stable signal timing, and reliable packet delivery.

Signal Integrity Optimization

The module incorporates advanced equalization and signal conditioning technologies that compensate for attenuation, modal dispersion, and connector losses. These features allow consistent performance across the maximum supported distance of 150 meters. The transceiver’s internal firmware continuously adjusts signal parameters to maintain stability, ensuring that link performance remains within tolerance levels under varying environmental and load conditions.

Physical Design and Form Factor

The Dell QSFP-40G-LM4 QSFP+ form factor is engineered for high-density networking environments where space efficiency and airflow optimization are critical. The compact footprint enables multiple modules to be installed within switches and routers without compromising cooling performance. The metal housing provides electromagnetic shielding, mechanical durability, and heat dissipation capabilities. Precision manufacturing ensures exact alignment of optical components, which reduces insertion loss and enhances optical coupling efficiency.

Connector Interface Specifications

The duplex LC connector interface is designed for compatibility with standard multimode fiber patch cables. The precision-polished ferrules ensure low return loss and stable optical coupling, reducing reflection and signal degradation. The locking mechanism provides a secure connection that resists vibration and accidental disconnection, which is especially important in high-traffic data center racks and network cabinets.

Hot-Pluggable Capability

The module supports hot-plug operation, allowing installation or replacement without powering down the host system. This feature supports continuous network availability and simplifies maintenance operations. Integrated protection circuitry prevents electrical surges during insertion, safeguarding both the module and the host device from damage.

Mechanical Durability Standards

The structural frame of the transceiver is constructed to withstand repeated insertion cycles while maintaining connector alignment and optical performance. The latching mechanism is reinforced for reliability, and the module housing is resistant to deformation under normal operating conditions. These characteristics ensure long service life even in environments where modules are frequently replaced or reconfigured.

Performance Characteristics and Transmission Reliability

The Dell QSFP-40G-LM4 module is engineered to provide consistent high-bandwidth performance with minimal packet loss and low latency. The optical transmitter utilizes precision laser sources tuned to specific wavelengths to ensure stable emission characteristics. Receiver sensitivity is calibrated to detect low-intensity signals while maintaining a high signal-to-noise ratio. Together, these capabilities allow the module to maintain stable communication links even under demanding traffic loads.

Distance Capability and Fiber Compatibility

The module supports transmission distances of up to 150 meters over multimode fiber, making it suitable for intra-rack, inter-rack, and short-reach campus connections. Compatibility with standard multimode fiber types ensures flexible deployment across existing infrastructure without requiring specialized cabling. The module automatically adapts to supported fiber characteristics, maintaining signal quality across different cable grades.

Error Detection and Correction

Built-in monitoring circuitry continuously evaluates signal quality and detects transmission anomalies. Error detection mechanisms identify discrepancies in transmitted data streams and allow corrective processes to maintain communication accuracy. This functionality reduces retransmissions, enhances throughput efficiency, and supports mission-critical network operations.

Performance

Temperature sensors within the module monitor internal conditions and adjust operational parameters to prevent overheating. Efficient heat dissipation is achieved through the metal enclosure and optimized internal layout. These thermal controls ensure stable optical output and prevent performance degradation caused by excessive temperature fluctuations.

Interface and Host Compatibility

The electrical interface of the QSFP+ module conforms to industry-standard specifications for 40Gb Ethernet connectivity. It uses high-speed differential signaling to communicate with the host device, ensuring reliable data transfer between the module and network hardware. The interface is engineered to maintain signal integrity even at high transmission speeds, preventing jitter and timing errors.

Power Consumption Efficiency

The module is optimized for low power consumption while maintaining full performance capability. Efficient circuitry design reduces energy usage and heat generation, which contributes to overall system efficiency. Lower power requirements also allow higher port density within network devices without exceeding thermal limits.

Operational Stability

Stable operation is maintained through a combination of precise component selection, thermal regulation, and advanced signal processing. The transceiver is designed to operate continuously without performance fluctuations, ensuring dependable connectivity for bandwidth-intensive applications.

Deployment Scenarios and Infrastructure Integration

The module is intended for integration into switches, routers, and network interface cards that support QSFP+ interfaces. Its short-range multimode capability makes it suitable for data center interconnects, aggregation layers, and high-speed backbone links. The compact design allows installation in high-density chassis systems where multiple ports operate simultaneously without interference.

Data Center Network Optimization

In data center environments, the module enables efficient high-speed communication between servers, storage arrays, and switching platforms. Its 40Gbps bandwidth supports large data transfers, virtualization workloads, and high-frequency transactions. The reliable optical link ensures consistent throughput even during peak traffic periods.

Enterprise Network Applications

Enterprise infrastructures benefit from the module’s ability to deliver fast and stable connectivity across core and distribution layers. The short-reach optical design is ideal for structured cabling systems within office buildings or campus facilities, providing high-capacity links without excessive power consumption.

Scalability Considerations

The transceiver’s standardized interface and high-bandwidth capability support scalable network architectures. As bandwidth demands increase, additional modules can be deployed to expand capacity without redesigning the existing infrastructure. This scalability ensures that networks can grow alongside organizational requirements while maintaining consistent performance characteristics.