The present application is directed an optical communication method. The method includes a step of receiving a signal at a single-polarization receiver. The method also includes a step of detecting, through the single-polarization receiver, the signal including a symbol with a pulse position modulation pulse and an additional modulation. The method also includes a step of decoding a first portion of bits carried by the symbol based on a position of the PPM pulse. Further, the method includes a step of decoding a second portion of the bits at the position through an additional modulation. The application is also directed to an apparatus for optical communication. In addition, the application is directed to an optical communication method which recovers two polarization components form the signal each carrying independent data. Further, the application is directed to an optical communication method that recovers two frequencies of the detected signal.

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