Moving to 400G? Make the Right Connections

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Many data centers are scaling up and considering or already upgrading technology to achieve next-generation data center connectivity. There’s growing demand to transmit more data faster at greater clarity and lower cost. 400G offers higher bandwidths and faster transmissions.

But once you make that investment, you should carefully consider your options for configuring and connecting.  If you know the strengths, limitations, and suitability of each option and assess your technical needs, you can make a better choice in fiber optic connectors and 400G cabling.

Two popular and widely available 400G transceiver form factors are QSFP-DD and OSFP.  For more information, read 400g transceiver form factors explained


Carefully consider your technical needs and budget with these parameters in mind:

  • Reach: the distance you need to transmit data
  • Latency: the nanosecond lag in information transmitted
  • Cost
  • Power Consumption
  • Flexibility – bending ratio. This is particularly important in tight spaces
  • BER (bit error rate)
  • Electronic security requirements.

Connectivity Options

Transceiver and Fiber Cabling

Your first option is to use a 400G transceiver with connectorized fiber cables.

  • 400G transceivers can transmit data greater distances than any other connection choice. They’re ideal for applications that require long distance transmissions. Transceivers are available for reaches from 100m to 10km.
  • It’s a bigger investment; they’re more expensive than AOCs, AECs, DACs.

AOCs, AECs, and DACs are pre-configured with transceivers attached at either end. Most come with QSFP-DD ends.


  • AOCs (active optical cables) are constructed from pure fiber and can reach up to 80km, transmitting signals longer distances than AEC or DACs;
  • are lightweight and compact;
  • have higher latency than DAC or AEC: 120 nanoseconds with digital chip; 20 nanoseconds with analog chip (our innovative analog AOC features low latency for HPC and supercomputing applications);
  • power consumption is greater than AEC or DAC. Using an analog chip reduces power consumption to 7.6W per cable end;
  • are more expensive than AECs or DACs but less expensive than a transceiver

400G AECs

This innovative new product, sold exclusively by select fiber optics suppliers, is a hybrid of copper and fiber, offering the best of both.


  • are less expensive than AOCs or standalone transceivers but more expensive than DACs;
  • have a reach of 7 meters: longer reach than DACs but not as far as AOCs;
  • Power consumption is 4.4W per cable end. This is an energy-saving option;
  • Lower latency than AOC (4 nanoseconds);
  • are smaller, lighter, and easier to maneuver than DACs but heavier and less flexible than AOCs;
  • are more compatible with other electronics, making electronic handshakes easier.

400G DACs

DACs are constructed of copper, not fiber. That makes them heavier and harder to maneuver but if initial investment, sustainability, and energy costs are important priorities, they will save money and energy. They’re a good option for short-distance transmission.


  • are the cheapest option;
  • have the shortest reach due to electromagnetic interference at longer reaches;
  • consume the least power;
  • have low latency;
  • are heavy, hard to maneuver in tight spaces. DACs are typically two and a half times heavier than AECs;
  • don’t provide the electronic security of fiber optic connectors.

Looking to upgrade your networks to 400G speeds? Our engineers can offer technical support and can guide you to the right connectivity solution. Vitex is based in New Jersey and has been helping data center operators migrate to ever higher speeds for more than two decades. To jumpstart your next project, contact us at

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