Can AOC And DAC Completely Replace Optical Modules?

1. Basic knowledge of AOC, DAC and optical modules

2. Can AOC and DAC completely replace optical modules?

3. Conclusion

With the rapid development of data centers and the increasing demand for high-bandwidth, large-capacity data transmission, the choice of network infrastructure has become particularly critical. In recent years, AOC (Active Optical Cable) and DAC (Direct Attach Cable) have been widely used in data centers as two common high-speed connection solutions. They have become the first choice for many data transmission scenarios due to their advantages such as high transmission rate, low latency and low power consumption. However, can AOC and DAC completely replace traditional optical modules? This is a question worth exploring in depth.

1. Basic knowledge of AOC, DAC and optical modules

1.1 AOC (active optical cable)

AOC is a hybrid cable that combines optical fiber and copper wire. It integrates an optoelectronic conversion module inside the cable, which can convert electrical signals into optical signals for long-distance transmission, and finally convert optical signals back to electrical signals after transmission through optical fiber. AOC is widely used in environments that require long-distance transmission, such as large data centers, high-performance computing and cloud computing platforms.

Advantages:

• Supports long-distance transmission (up to tens of meters or even further)

• High-speed data transmission capability (such as 100G, 400G)

• Low power consumption and small size

Disadvantages:

• Relatively high cost

• Poor flexibility (cable of fixed length)

1.2 DAC (passive cable)

DAC is a copper wire cable without built-in electronic module, which transmits electrical signals in copper conductors. DAC is generally used for short-distance data transmission, usually for high-speed communication between switches and servers. It has the advantages of simple structure, low cost and low power consumption, but because there is no optical fiber module, it is suitable for shorter transmission distances.

Advantages:

• Low cost

• Extremely low power consumption

• Suitable for short-distance transmission (5-10 meters)

Disadvantages:

• Limited transmission distance

• Low applicable bandwidth (usually supports less than 100G)

1.3 Optical Modules

Optical modules usually refer to devices used to convert electrical signals into optical signals for long-distance transmission. Optical modules connect different devices through optical fibers and are widely used in large-scale data centers, Internet exchange nodes and telecommunication networks. Common optical module standards include SFP+, QSFP, etc. The advantage of optical modules is that they support long-distance, high-bandwidth transmission and are suitable for large-scale network architectures.

Advantages:

• Supports extremely long-distance optical fiber transmission (up to hundreds of    meters or even thousands of kilometers)

• High-bandwidth transmission capability (such as 400G, 800G)

• Strong applicability and high flexibility

Disadvantages:

• High cost

• Relatively high power consumption

2. Can AOC and DAC completely replace optical modules?

2.1 Transmission distance and bandwidth limitations

AOC and DAC differ significantly from optical modules in transmission distance and bandwidth. Since DAC uses copper wire for data transmission, the maximum transmission distance is usually limited to 5-10 meters. For short-distance connections within data centers, DAC is undoubtedly the most cost-effective choice. However, in scenarios that require longer transmission distances and higher bandwidths (such as 100G and above), AOC can provide better support. Although AOC supports longer transmission distances (usually up to tens of meters), its transmission distance is still limited compared to optical modules.

2.2 Cost and Power Consumption

In terms of cost and power consumption, AOC and DAC perform well. DAC has a simple structure and no built-in electronic modules, so it has low cost and very low power consumption, which is particularly suitable for short-distance connections. Compared with traditional optical modules, although AOC is more affordable, it is still higher than DAC and has lower power consumption. Therefore, it has the potential to replace optical modules to a certain extent, especially when long-distance transmission and low bandwidth are required.

However, optical modules still have advantages under ultra-high bandwidth requirements (such as 400G and above), and the power consumption of optical modules is usually high, especially in long-distance and high-bandwidth transmission. Therefore, although AOC and DAC can be replaced in low-power application scenarios, optical modules are still an irreplaceable choice in applications that require ultra-high bandwidth and long-distance transmission.

2.3 Flexibility and Applicability

Optical modules have greater flexibility and applicability, and can choose different types of optical fibers and transmission distances according to different needs. The use scenarios of AOC and DAC are relatively fixed, especially DAC, which is only suitable for short-distance connections. Although AOC provides more options, they may not be flexible enough in some application scenarios because they are fixed-length cables. In contrast, optical modules can flexibly select appropriate transmission media and equipment configurations according to actual needs.

3. Conclusion

Although AOC and DAC can provide excellent performance in some data center applications, especially in short-distance transmission and lower bandwidth requirements, their advantages in cost, power consumption and transmission distance make them an ideal alternative. However, in environments that require ultra-high bandwidth, large-scale data transmission and long-distance connections, optical modules are still an irreplaceable choice.

Therefore, AOC and DAC can replace optical modules in certain specific application scenarios, especially in short-distance connections within data centers, but to completely replace optical modules, it is still necessary to overcome the limitations of transmission distance, bandwidth and flexibility. In the future, with the further development of technology, AOC and DAC may play an important role in a wider range of application scenarios, but optical modules will still maintain their important position in areas such as high bandwidth and long-distance connections.