How a new AWS optical network solution delivers unmatched scale and efficiency across its global infrastructure

The custom-built Dense Wavelength Division Multiplexing (DWDM) transponder from AWS delivers 73% more bandwidth than the previous version, while reducing power consumption by nearly 35%

When you stream a movie, make an online purchase, or use a cloud-based application, your data travels across vast networks of fiber optic cables spanning cities, countries, and continents. Behind the scenes, AWS is constantly innovating to keep our massive digital highway system running smoothly and efficiently for customers around the world.

To further improve speed and efficiency, we built the AWS DWDM transponder system, specialized networking equipment designed for our global network. Think of a DWDM transponder as a sophisticated high-speed rail system. Just as a railway network can transport multiple trains simultaneously on parallel tracks, this device securely moves different streams of data through a single fiber optic cable using different wavelengths of light, like dedicated tracks that can carry different types of cargo without interference. While traditional transponders offer standard transportation systems that serve general purposes, we built our own custom networking pathways specifically optimized for our unique delivery needs, resulting in better performance and value for our customers.

As the only cloud provider with custom DWDM transponder technology at this scale, AWS delivers unmatched global performance and efficiency. The first AWS DWDM transponder for metro connections proved so successful that our team developed a new version with enhanced capabilities. AWS network infrastructure operates on two scales. Metro connections link data centers within a single Region for distances up to 400 kilometers, while long-haul connections span thousands of kilometers to connect different Regions together.

AWS DWDM transponder sled

In just five months, a new version of the AWS DWDM transponder was developed with added features and specialized tools to handle long-distance connections. Development began in January 2024, and by February 2025, the systems were fully deployed for metro networks carrying customer traffic. In July 2025, the first long-haul connection spanning over 1,500 kilometers went live successfully.

While the initial AWS DWDM transponder worked well for metro applications, long-haul connections presented greater challenges. Spanning hundreds to thousands of kilometers, these links require advanced technology and careful capacity optimization due to substantial investments in fiber infrastructure, repeaters, and amplifiers. Long-distance connections often traverse challenging terrains like deserts or lakes where infrastructure and fiber availability are limited, making it critical to maximize bandwidth per fiber compared to metropolitan areas.

AWS’s first long-haul deployment using the proprietary DWDM technology delivered 73% more bandwidth than the previous version at the same cost, while reducing power consumption by nearly 35% and accelerating innovation cycles. For customers, this means faster data transfer speeds, improved application performance, and more sustainable operations without increased costs. This achievement makes AWS the first cloud provider to successfully develop and deploy custom DWDM technology for both metro and long-haul applications, with plans for rapid global expansion.

From light signals to cloud infrastructure

The story of this innovation begins with learning more about DWDM, which emerged in 1996. DWDM is crucial because it maximizes the use of existing fiber infrastructure. Without DWDM, you’re essentially using only one lane of a multi-lane highway. You might send one signal or a few widely spaced signals down the fiber, but you’re wasting most of the available capacity that the fiber could handle. In essence, DWDM transforms a single fiber into a high-capacity data super highway by utilizing the full potential of the available optical spectrum.

By 2008, advancements in coherent technology, used in DWDM transponders, revolutionized optical networking. Coherent technology is an advanced optical method that encodes data using both the brightness and timing of laser light, allowing much more information to be packed into fiber optic cables for faster, longer-distance transmission. Traditional optical systems were like Morse code telegraphs; simply turning light on and off to represent digital data. Coherent technology, however, is like upgrading from those telegraphs to modern digital phone calls. This breakthrough technology increased data transmission capacity through existing fiber optic cables.

Building better connections, closer to home   

Over a dozen years ago, AWS began developing its own data center hardware, starting with network switches. Rather than procuring standard industrial-grade switches from vendors, which included many unnecessary features for efficient cloud applications, we focused on the essential components and built custom software tailored to our specific needs. This approach not only resulted in significant improvements in security and availability, but technology optimized for the unique requirements of AWS infrastructure. The same philosophy was later applied to metro and long-haul connections through the development of our custom-built DWDM transponder.

Rather than simply purchasing complete systems from traditional vendors, we took a different approach: combining specialized optical modules from select technology partners with our own expertise in building network platforms. Our team created the surrounding hardware (like the chassis, short reach connections, and control systems) and adapted our existing software with vast, integrated network tools to work with this new technology, allowing for more flexible and efficient network infrastructure. By late 2020, we had deployed the first version of the AWS DWDM transponder for metro applications. In addition to better integration, the system proved to be more reliable compared to other products in the market.

“This represented a significant shift in how data transmission systems are built,” explained Omid Momtahan, Sr. Network Dev Manager of AWS Network Product Development, who led the project. “After we successfully demonstrated and deployed the technology for metro connections, we proved that a simplified, customized approach could deliver superior performance, higher availability, and agility in operations and deployment. This innovation challenged the industry’s traditional model of complex, all-in-one solutions, showing that specialized systems could be both more effective and more economical.”

The technology behind the transformation

The latest version of the AWS DWDM transponder builds upon the success of the first version with enhancements in several key areas:

• Advanced fabrication for better performance

Transitioning to smaller, more efficient manufacturing technology has at least doubled channel capacity while reducing power consumption, demonstrating significant performance improvements. This was achieved by utilizing recent advancements in electrical and photonics chip manufacturing technology. It also allowed us to maintain the same total bandwidth with half the number of channels (32 vs. 64) across the fiber spectrum.

• Enhanced resilience

Through this customized solution, we developed hardware that demonstrated a 50% lower [max] failure rate than our prior third-party transponder, according to internal measurements. This increased link availability ensures minimal to no interruption for customers. Meaning fewer service disruptions and more consistent connectivity.

• Flexible data transmission

The new AWS DWDM transponder delivers flexible data transmission rates with the ability to adjust in 100-gigabit increments. Think of it like adjusting water pressure in a hose. While traditional systems only offer “high” or “low” settings, our system can fine-tune the flow of data in small adjustments. This flexibility allows us to optimize performance for each network’s unique characteristics and achieve capacity improvement.

• Unified system architecture

The latest iteration creates a unified operating environment across data centers, metro connections, and long-haul networks, using the same hardware, operating system, and tools. This integration enhances reliability and enables granular security controls, real-time threat detection, and rapid updates without third-party risks. AWS support teams use a single toolset across all networking equipment, enabling faster issue resolution and more stable connections. This unified approach allows proactive problem identification before customer impact, resulting in more reliable service, reduced downtime, stronger security, and consistent connectivity.

Benefits beyond the network

Beyond performance improvements, this innovation delivers substantial environmental benefits. Unlike traditional vendor solutions, our tailored approach allows for precise power management across the network. The unified architecture eliminates redundant systems, while granular control over data rates ensures optimal efficiency for each connection. These advancements not only enhance network performance but also contribute significantly to AWS’s environmental commitments.

While environmental efficiency represents one major advantage of our custom approach, control over the entire hardware stack delivers equally important security benefits. A significant advantage of AWS investing in its own network hardware for over a decade is the enhanced security posture it enables across our infrastructure. All traffic that passes outside of AWS control between regions has encryption applied at the network level, adding an additional layer of protection for customer data across our global network. By controlling the entire hardware stack, we can implement comprehensive security measures that would be challenging with third-party solutions. Our custom hardware, like the AWS DWDM transponder, is designed with security as a foundational principle, delivering infrastructure built to support compliance criteria while maintaining expected performance and reliability.

Development agility is another key advantage. By building in-house, we can implement new optimized solutions faster than traditional providers. This rapid innovation cycle allows us to stay ahead of evolving customer needs and network demands.

Looking to the future

This initial long-haul deployment represents just the first implementation of the in-house technology across our extensive long-haul network. We have already extended deployment to Europe, with plans to use the AWS DWDM transponder for all new long-haul connections throughout our global infrastructure.

This transition from traditional vendors to purpose-built internal systems represents more than just technical advancement, it reflects a fundamental shift in how cloud infrastructure evolves to meet customer needs. Our end-to-end unified architecture, sharing the same hardware, operating system, and tools from data centers to long-distance networks, streamlines operations and strengthens service reliability for AWS customers. The result is a cloud experience that continues to improve in ways that matter most to customers, powered by AWS’s commitment to continuous innovation.