Communication with ultrashort pulses and parallel-to-serial and serial-to-parallel converters

A communication method employing ultrashort pulses with parallel-to-serial and serial-to-parallel converters is analyzed in terms of the number of bits that can be encoded in a packet burst, the exact temporal profile of the packet, and the system capacity. The temporal profile of the transmitted pulses is shown to consist of a sequence of chirped pulses, that were also verified experimentally. The parallel-to-serial transmitter works as follows: An incident ultrashort pulse´s frequencies are modulated by a collection of linear phase functions, generated by the interference of monochromatic beams. By a four-wave mixing (4WM) process the linear phase function of the interference pattern is read out by the incident short pulse. The output is therefore a replication of the input pulse at different time shifts, according to the slope of the phase functions. The generated pulses carry the information to be transmitted, in a format of a packet of bit pulses with on-off keying. To determine the capacity of a fiber link employing a parallel-to-serial transmitter and a serial-to-parallel receiver at its two ends, several additional design issues have to be introduced