Working principle of USB active optical cable

USB Active Optical Cable (AOC) is a technology that combines the advantages of optical fibers and traditional electrical connectors. It uses photoelectric conversion chips integrated at both ends of the cable to organically combine optical fibers and cables. This design allows AOC to provide a range of advantages over traditional copper cables, particularly in long-distance, high-speed data transmission. This article will mainly analyze the working principle of USB active optical cable.

Advantages of USB active fiber optic cable

The advantages of USB active fiber optic cables are very obvious, including longer transmission distances. Compared with traditional USB copper cables, USB AOC can support a maximum transmission distance of over 100 meters, making them very suitable for applications that require crossing large physical spaces, such as security cameras, industrial automation, and data transmission in medical equipment. There are even higher transmission speeds, with USB 3.0 AOC cables capable of up to 5 Gbps, while newer standards such as USB4 can support transmission speeds of up to 40Gbps or even higher. This means that users can enjoy faster data transfer speeds while maintaining compatibility with existing USB interfaces.

In addition, it also has better anti-interference ability. Due to the use of fiber optic technology, USB AOC has excellent electromagnetic compatibility (EMC), which can effectively resist electromagnetic interference (EMI). This is very important for applications in strong electromagnetic environments, such as precision instrument connections in hospitals or factory workshops. Lightweight and compact, compared to traditional copper cables of the same length, USB AOC is more lightweight and flexible, reducing its weight and volume by over 70%. This feature is particularly advantageous for mobile devices or installation scenarios with strict space requirements. In most cases, USB AOC can be plug and play directly without the need to install any special driver software.

Working principle

The working principle of USB AOC is based on four main components.

1. Electrical signal input: When a device sends data through a USB interface, the generated electrical signal first reaches one end of the AOC. The electrical signals here are the same as those used in traditional copper cable transmission, ensuring compatibility with existing USB standards.

2. Electric to optical conversion: One or more vertical cavity surface emitting lasers are embedded at one end of the AOC cable, which are responsible for converting the received electrical signals into optical signals.

3. Fiber optic transmission: Once electrical signals are converted into optical signals, these optical pulses will be transmitted over long distances along the fiber optic cable. Due to the very low loss characteristics of optical fibers, they can maintain high data transmission rates even over long distances and are almost unaffected by external electromagnetic interference.

4. Light to electricity conversion: When the light pulse carrying information reaches the other end of the AOC cable, it will encounter a photodetector. This device is capable of capturing optical signals and converting them back into their original electrical signal form. Subsequently, after amplification and other necessary processing steps, the recovered electrical signal will be transmitted to the target device, completing the entire communication process.