Optical Packet Switch with Recursive Parametric Wavelength Conversions

This paper proposes a scheme to increase possible patterns of wavelength-conversion for an optical packet switch (OPS) with parametric wavelength converters (PWCs) by obtaining additional converted wavelengths using the existing resources. It is called a recursive parametric wavelength conversion (RPWC) scheme. A PWC uses a pump wavelength to define the original and converted wavelengths, called wavelength conversion pairs. None of conversion pairs from any PWCs can sometime support the original and available converted wavelength, although some wavelengths at the requested output fiber are available. Since the original wavelength is not converted, some packet losses may occur. Several conversion pairs are wasteful since they are not utilized. In RPWC scheme, unused conversion pairs are used to create additional conversion pairs. The OPS allows each wavelength to be converted using combination of unused conversion pairs using more than one PWCs, instead of using only a single PWC as in a conventional scheme. Numerical results via simulation show that the RPWC scheme achieves lower packet loss rate than the conventional scheme. To show the feasibility of the RPWC scheme, we develop a prototype of an optical switch with RPWC and demonstrate it in experiment.