Duobinary pulse shaping for optical transmission systems employing pulse amplitude modulation techniques

A method for receiving information, said method comprising the steps of:

• receiving an optical signal, said optical signal is encoded using pulse amplitude modulation and duobinary encoding techniques to encode a plurality of bits;
• detecting a power level of said received optical signal;
• and
• mapping said detected power level to a plurality of bits, wherein a 2N−1 level signal is mapped to a corresponding voltage value using a reordered set of said 2N−1 levels such that following a squaring operation the received signal appears as a modulo N operation.

A system for transmitting information, said system comprising:

• a precoder for converting a plurality of input bits to an N level signal;
• an adder for adding a current N level signal to a previous N level signal to produce a 2N−1 level signal, wherein said 2N−1 level signal is mapped to a corresponding voltage value using a reordered set of said 2N−1 levels such that following a squaring operation at a receiver a received signal appears as a modulo N operation;
• and
• a digital to analog converter for converting said 2N−1 level signal to an optical signal for transmission to said receiver.

A system for receiving information, said system comprising:

• an input port for receiving an optical signal, said optical signal is encoded using pulse amplitude modulation and duobinary encoding techniques to encode a plurality of bits;
• a power detector for detecting a power level of said received optical signal;
• and
• a slicer for mapping said detected power level to a plurality of bits, wherein a 2N−1 level signal is mapped to a corresponding voltage value using a reordered set of said 2N−1 levels such that following a squaring operation the received signal appears as a modulo N operation.