The solution relates to a method and device for transmitting optical signals in optical networks using a technique called “polarization multiplexing.” This method, commonly used in long-distance communications, has the potential to enhance reflective passive optical networks (PON).

PONs are characterized by an optical line terminal (OLT) that sends optical signals to multiple optical network units (ONUs) via bidirectional optical fibers. In reflective networks, for safety and cost reasons, ONUs do not have active sources like lasers or LEDs. Instead, the continuous optical signal from the OLT is reflected and locally modulated to transmit data back to the central terminal.

The current challenge is that polarization multiplexing requires precise control of the optical signal’s polarization, achievable only near the laser source. This makes it difficult to implement in reflective ONUs, where the incoming laser signal has an uncertain polarization.

This invention aims to overcome this limitation by proposing innovative solutions to integrate polarization multiplexing into reflective passive optical networks. The goal is to improve network performance while maintaining the simplicity of user-end devices.