40G Active Optical Cable (AOC) is one of the best solutions available for deploying 40G Ethernet. This low-power yet high-performance cable accepts the same electrical signals as a 40G DAC (Direct Attach Cable). It has 40G QSFP+ optical modules on both ends. However, you can also buy an active optical cable that has a 40G module on one end and 4 x LC duplex connectors or 4 x 10G optical modules on the other end.
Active Optical Cable
What is 40G active optical cable?
An active optical cable is a cable that accepts electrical input like any copper cable, but with a fiber optic cable between the connectors. In these cables, electricity to light conversion is achieved at the end of the cable. This cable technology provides better reliability, distance performance and speed while maintaining absolute compatibility with conventional electrical interfaces. Active optical cables are composed of optical modules, multiple optical fibers and control circuits.
These cables contain four (10 GBps) data lanes and operate at a total bandwidth of 40Gbps. Active optical cables are ordered by connector type and cable length. Today, we have many options on the market and easy access to active optical cables that fit your existing network infrastructure. Additionally, the availability of breakthrough active optical cables allows us to interconnect 10G and 40G networks. Let us share several 40G active optical cables that are widely used today:
Construction of Active Optical Cables
Any active optical cable has an optical module at both ends. An optical module contains two: a transmitter and a receiver. Both ends of an active optical cable can be connected to Ethernet. In order to convert the received data in electrical format and transmit the received data in optical format, electrical to optical converters and optical to electronic converters are also used at either end of the cable. For sending, LASER or LED is used, while receiving is handled by APD detector or PIN.
Why prefer active optical cables?
Copper cables are notoriously bulky and, therefore, difficult to manage in a data center environment. Additionally, electromagnetic interference limits the reliability and performance of copper. By choosing an active optical cable, you can:
Safe and reliable transmission;
higher bandwidth and longer coverage;
limited EMI exposure;
Low power consumption;
low bit error rate;
Compared to copper cables, it is lighter in weight and smaller in size.
The difference between active optical cable and active copper cable and passive copper cable
In passive copper cables, there is a copper-based electrical connection between both ends of the cable. In active copper cabling, additional circuitry can be used to better handle the data, but the transmission is through the copper cabling. In an active optical cable, the optics are embedded in the connector, and data transmission is accomplished through multimode fiber. Therefore, copper cables can be active cables or passive cables. However, fiber optic cables can only be active cables.
40G Active Optical Cable with 40G Active Copper Cable and 40G QSFP+ Optical Module
As we all know, 40G active copper cables and 40G QSFP+ optical modules are two other options available for 40G network deployment. However, experience has shown that 40G active optical cable is considered a better choice compared to other options. 40G active optical cables are lighter, thinner, and allow for steeper bend radii. Therefore, its implementation is much easier than 40G active copper cable. For 40G QSFP+ optical modules and 40G active optical cables, the latter will dominate again. When using QSFP+ optical modules, you will need additional fiber patch cables. Also, the cleanliness issue of QSFP+ optical modules is another big hassle. On the other hand, this cleaning hassle has nothing to do with 40G active optical cables.
in conclusion
In view of the above facts, it can be concluded that compared to 40G active copper cables, 40G active optical cables have longer transmission distances and are easier to deploy. Also, active optical cables are a cheaper solution for 40G migration with lower return loss and less insertion loss.
