T1-QSFP56-DD-400G-SR4: High-Speed 400G Transceiver for Short-Reach MMF Links

The T1-QSFP56-DD-400G-SR4 is a high-performance 400GBASE-SR4 optical transceiver designed for short-reach, high-speed data transmission over multimode fiber (MMF). Using the QSFP56-DD form factor and PAM4 modulation, this module delivers 400 Gbps aggregate bandwidth over parallel OM4 fiber for distances up to 50 meters, making it a practical and efficient solution for high-density data center connectivity.

The explosion of cloud computing, artificial intelligence, and big data analytics is fundamentally transforming data center infrastructure, driving a surge in demand for high-speed interconnect transceivers. These transceivers play a critical role in enabling high-bandwidth, low-latency connections between servers, storage, and network devices, supporting the ever-increasing data traffic and performance requirements of modern digital ecosystems. As workloads become more data-intensive and distributed—especially with the rise of AI clusters, hyperscale architectures, and edge computing—data centers must rely on advanced transceivers to efficiently handle massive volumes of information, ensuring seamless communication, scalability, and real-time analytics essential for competitiveness in today’s digital landscape. 

Key Characteristics 

•     Form Factor: QSFP56-DD (Double Density) 

•     Data Rate: 400 Gbps (4 × 100 Gbps) 

•     Wavelength: 850nm 

•     Fiber Type: Multimode Fiber (MMF) 

•     Reach: Up to 50 meters over OM4, 30 meters over OM3 

•     Connector Type: MPO-12/APC 

•     Modulation: PAM4 

•     Hot-Pluggable: Easy to integrate and swap in dense environments 

•     Standards Compliance: IEEE 802.3cm, QSFP-DD MSA 
•     Power Efficiency: Optimized for low power consumption in high-density environments 

Working Principles

The T1-QSFP56-DD-400G-SR4 transceiver transmits data using four parallel optical lanes, each operating at 100 Gbps using PAM4 modulation over 850nm wavelength. The module uses an MPO-12 connector to send and receive signals over OM4 multimode fiber, supporting transmission distances up to 50 meters. Designed for high-density QSFP-DD slots, it allows data centers to scale up bandwidth without increasing port count, while maintaining energy efficiency and signal integrity over short-reach connections.

Primary applications

Data Center Leaf-Spine Architectures: Enables rapid aggregation between top-of-rack switches and spine switches. 

Server and Switch Interconnects: Supports high-speed server uplinks and switch-to-switch links. 

Cloud Infrastructure: Scales to meet growing bandwidth needs in hyperscale environments. 

Storage Area Networks (SANs): Provides fast access between compute and storage layers. 

AI/ML Clusters: Facilitates high-bandwidth connections between compute nodes in training clusters. 

Why the T1-QSFP56-DD-400G-SR4 Matters

With the exponential growth in east-west traffic, cloud services, and AI workloads, data centers need transceivers that offer high bandwidth, low power, and short-reach efficiency. The T1-QSFP56-DD-400G-SR4 meets these demands by providing a cost-effective, scalable path to 400G over MMF infrastructure. It plays a critical role in enabling faster, more agile network fabrics—paving the way for modern high-performance data center environments.