How secure is laser communications technology?

Wireless laser communication, also known as free-space optical (FSO) communication, is a technology that uses lasers to transmit data through the atmosphere. FSO communication is inherently more secure than traditional RF (Radio Frequency) and mmWave (millimetre wave) technology for several reasons.

1. Use of higher frequencies for transmission

Laser communication operates at much higher frequencies than RF and mmWave technology. This means that not only are the electromagnetic waves or beams capable of transmitting a lot more bits per second than RF and mmWave, but the beams are also much more narrow and harder to detect and decode. 

For example, on a one (1) kilometer link between two laser communications devices like CENTAURI, the extremely narrow laser beams (in millidegrees) carrying data from point-to-point create a spillover zone of less than a meter at the receiving end of the link.

At these distances, any attempt to intercept communication within this zone would be immediately visible in the systems used to track the performance of links, triggering alarms.

2. Directionality

Laser beams are highly directional and can be focused into a very narrow beam. This means that the signal can be targeted and directed precisely to the intended receiver, making it difficult for eavesdroppers to intercept the transmission.

Even if an interception attempt is made the interceptor would need to be positioned exactly parallel to the laser source -- with millidegree precision --- in order to successfully enough light through any device used as a receptor to make sense of the data being transmitted.

This would be made even more challenging due to vibrations that affect the movement of the laser source.

3. Interception detection

FSO systems use sophisticated optical detection methods that can detect any interruption or interference in the signal path. If the signal is disrupted, the link drops, data stops flowing, and the system can immediately detect it and take action to prevent further interception or unauthorized access.

4. Physical security

Since laser communication systems require a clear line of sight between the transmitter and receiver, physical security measures can be put in place to protect the equipment from tampering or interference. This makes it much more difficult for unauthorized parties to access the system and intercept the data.

Again, because laser communication uses a different part of the EM spectrum than RF and mmWave, it is immune to RF interference. This also makes laser communications an ideal solution for operating in highly congested environments.

This same trait makes laser communications immune to "jamming," as well.

In Conclusion

Overall, the unique combination of physical traits of the communication medium, coupled with additional technical security measures that limit access to the monitoring and management systems used to deploy and operate communication links make laser communication an ideal choice for applications that require high-speed data transmission with a high level of security.