"15km" on an optical module indicates the maximum distance the module can reliably transmit optical signals without significant degradation.

In fiber optic communication, the 15km specification refers to the maximum transmission distance over which the optical module can maintain a stable signal with minimal loss, interference, or latency (as seen in FPV and long-range video transmission systems) . This distance is determined by factors such as the fiber core diameter, signal attenuation, and the quality of the optical components.

Key Technical Details

• Fiber Core Diameter: The "mm" part often refers to the fiber's core size, for example, 0.27mm. A smaller core allows higher bandwidth and lower signal dispersion but requires precise alignment during installation .
• Signal Attenuation: Optical signals weaken as they travel through the fiber, measured in decibels per kilometer (dB/km). A low attenuation rate ensures the signal can reach the full 15km without noticeable degradation .
• Bandwidth and Latency: Modules designed for 15km transmission can support high-definition video (1080p or higher) with low latency, often under 15ms, making them suitable for real-time applications like drone FPV .

Practical Implications

Using a 15km optical module means you can reliably transmit data or video over long distances, such as between a drone and a ground station, without relying on traditional RF links that are limited by interference or terrain. The module's design ensures signal integrity, even in challenging environments, by leveraging single-mode fiber and precise optical engineering . In summary, 15km indicates the optical module's effective range, while the associated fiber specifications (core diameter, attenuation, and optical power) define how well the signal maintains quality over that distance .