Efficient all-optical wavelength converter using saw-tooth pulses

In this paper we investigate the use of pulse shaping of the signal to be converted into a saw-tooth waveform (i.e. a pulse with leading/trailing edges of a constant intensity gradient), to improve the performance of the converted signal. Due to their linear gradient, when saw-tooth pulses are used as the XPM pump, they induce a constant frequency shift to the signal. These new frequency components are highly spectrally confined and discretely separated from the CW carrier, thus allowing most of the wavelength converted signal energy to pass through the subsequent offset filters, thereby improving the overall optical signal to noise ratio (OSNR) and the overall system performance. Similarly, self-phase modulation (SPM) of saw-tooth pulses is more confined, giving more flexibility on the choice of the pump and signal wavelength allocations.