In the era of cloud computing, big data, and artificial intelligence, data centers are experiencing an unprecedented surge in internal and inter-facility data traffic. For short-range connectivity scenarios—such as server-to-top-of-rack (ToR) switches, intra-data center row-to-row links, and small-scale data center interconnections (DCI) within 2KM—the demand is clear: massive bandwidth, low latency, and optimized costs.

Traditional 100G optical solutions, however, often fail to strike this balance. 100G SR4 modules are limited to 100 meters, unable to cover 2KM short-range needs, while 100G LR4 modules rely on expensive dense wavelength division multiplexing (DWDM) components, driving up deployment costs for short distances.

Enter the 100G CWDM 2KM optical module—a game-changer that leverages Coarse Wavelength Division Multiplexing (CWDM) technology to deliver 100G bandwidth over 2KM, filling the critical gap in short-range high-speed data center connectivity.

I. Technical Core: CWDM Technology Redefines Short-Range 100G Connectivity

The 100G CWDM 2KM module’s competitive edge lies in its innovative application of CWDM technology, which addresses the core pain points of short-range high-bandwidth connectivity through “wavelength efficiency” and “cost optimization”.

At the heart of the module is the Coarse Wavelength Division Multiplexing (CWDM) architecture. Unlike traditional single-wavelength modules, it aggregates four independent 25G signals onto a single pair of optical fibers using four distinct CWDM wavelengths (typically spanning 1270nm-1610nm).

This design eliminates the need for multiple fiber pairs to transmit 100G bandwidth, reducing fiber resource consumption by 75% compared to parallel fiber solutions like 100G SR4. For data centers with limited fiber duct space, this means avoiding costly fiber expansion projects.

For example, a medium-sized cloud data center upgrading from 40G to 100G connectivity between rows can reuse existing single-mode fiber pairs, cutting fiber-related infrastructure costs by over 40%.

To ensure stable 100G transmission over 2KM, the module integrates three key performance-enhancing features: First, high-efficiency DFB lasers for each wavelength, with a stable output power of +2dBm to +4dBm, effectively minimizing signal attenuation over short-to-medium fiber runs.

Second, a compact CWDM multiplexer/demultiplexer (MUX/DEMUX) integrated into the module, which reduces signal insertion loss to less than 3dB—far lower than external CWDM devices, ensuring minimal latency (typically <1μs per kilometer) critical for real-time data processing.

Third, low-noise PIN detectors with a receive sensitivity of -14dBm per channel, enabling the module to accurately decode 25G signals even after 2KM transmission, maintaining a bit error rate (BER) as low as 10⁻¹², which meets the strict reliability requirements of data center mission-critical applications.

Additionally, the module excels in practicality and compatibility: It adopts the hot-swappable QSFP28 form factor, seamlessly compatible with most mainstream data center switches (e.g., Cisco Nexus, Arista 7050X) and servers, eliminating the need for hardware replacements.

Its operating power consumption is as low as 3.5W—25% lower than 100G LR4 modules—aligning with data centers’ “green and energy-saving” goals, as reduced power usage translates to lower cooling costs and a smaller carbon footprint.

II. Scenario Applications: Powering Key Short-Range Data Center Use Cases

The 100G CWDM 2KM module’s combination of “100G bandwidth”, “2KM coverage”, and “cost efficiency” makes it the ideal choice for three core short-range data center scenarios:

1. Intra-Data Center Row-to-Row & Rack-to-Rack Connectivity

In large-scale data centers, server racks are often arranged in rows, with distances between rows ranging from 100 meters to 2KM. ToR switches in each row need to connect to end-of-row (EoR) or middle-of-row (MoR) aggregation switches, requiring high-bandwidth, low-latency links. A global e-commerce company, for instance, deployed 100G CWDM 2KM modules in its primary data center to connect 50+ ToR switches to EoR switches across 1.5KM. By using CWDM technology, the company reduced fiber pair usage from 16 (for 100G SR4 parallel fibers) to 2, simplifying cable management and cutting initial deployment costs by 30%. The low latency (<1.5μs) also ensured smooth real-time processing of peak-hour order data.

2. Small-Scale Data Center Interconnection (DCI)

For enterprises or cloud providers with multiple small data centers (e.g., campus-style data centers) within 2KM, interconnection requires 100G bandwidth to support data synchronization and load balancing. A financial services firm with two data centers 1.8KM apart used 100G CWDM 2KM modules to build a DCI link.

Compared to 100G LR4 modules, the CWDM solution eliminated the need for expensive DWDM transponders and dispersion compensation units, reducing per-link costs by 45%. The module’s stable performance also ensured 24/7 uninterrupted transmission of sensitive financial data, meeting regulatory compliance requirements.

3. High-Performance Computing (HPC) Cluster Connectivity

HPC clusters—used in scientific research, AI model training, and industrial simulation—require ultra-fast inter-node communication, with cluster nodes often distributed across 500 meters to 2KM. A research institute specializing in climate modeling deployed 100G CWDM 2KM modules to connect 128 HPC nodes in its cluster.

The module’s 100G bandwidth and low latency (<1μs) enabled the cluster to process large-scale climate datasets 20% faster than with previous 40G links, while the CWDM design reduced fiber cabling complexity, making maintenance and future upgrades easier.

III. Industry Value: Accelerating Data Center Transformation with Cost-Effective High Bandwidth

For the data center and optical communication industries, the module is more than just a product—it is a catalyst for “efficient digital infrastructure” development. As data center traffic grows at a compound annual rate of 35%, short-range high-bandwidth connectivity has become a bottleneck for many enterprises.

This module addresses this bottleneck by offering a “middle-ground” solution: faster than 40G modules, more cost-effective than 100G LR4 modules, and longer-reaching than 100G SR4 modules.

By reducing fiber usage and hardware costs, the 100G CWDM 2KM module lowers the barrier to 100G adoption for medium-sized data centers and enterprises.

This aligns with the global trend of “data center democratization”, where even small-to-medium businesses can access high-bandwidth infrastructure to support digital transformation.

Furthermore, the module’s popularity is driving innovation in the short-range optical component ecosystem. Upstream chip manufacturers are developing more compact, low-cost CWDM laser arrays, while downstream switch vendors are integrating CWDM compatibility into entry-level 100G switches—creating a virtuous cycle of cost reduction and performance enhancement.

Looking ahead, as AI workloads and real-time data processing demand continue to rise, the need for 100G+ short-range connectivity will only intensify. The 100G CWDM 2KM module, with its proven bandwidth, range, and cost advantages, will remain a cornerstone of short-range data center connectivity—enabling data centers to scale efficiently, reduce costs, and keep pace with the ever-growing demands of the digital age.