Optical Wireless Signal Phase Mask Encoding

The patent converts the harmful effect of external interference light into a beneficial filtering mechanism by using phase encoding. The receiver applies a specific phase pattern that causes interference light (which lacks the encoded phase structure) to cancel itself out through destructive interference, while the desired signal with the matching phase pattern constructively interferes. This transforms the harmful interference into a self-filtering mechanism.

The patent changes the phase parameter of the optical signal by applying a phase pattern to the wavefront. This phase modulation creates a unique signature for the desired signal that distinguishes it from interference. The receiver detects and compensates for this phase change, enabling reliable decoding even in the presence of strong external light sources.

The patent introduces a phase mask as an intermediary element that encodes the signal with a secret phase pattern. This phase mask acts as a physical key that only the authorized receiver possesses. The encoded phase information serves as a mediator that enables secure communication without requiring complex cryptographic protocols, as the phase encoding itself provides the security mechanism.

The patent applies phase encoding to the optical signal before transmission as a preliminary security measure. This pre-encoding with a secret phase pattern ensures that even if the signal is intercepted, the eavesdropper cannot decode it without knowing the specific phase pattern. The security is built into the physical layer before transmission occurs.