Simultaneous label swapping and wavelength conversion of multiple independent WDM channels in an all-optical MPLS network using PPLN waveguides as wavelength converters

This paper presents the demonstration of all-optical simultaneous label swapping and wavelength conversion of multiple independent wavelength-division multiplexed (WDM) channels using periodically poled lithium niobate (PPLN) waveguides as wavelength converters. Label swapping is one of the required functions in the physical layer for efficient data flow control in the proposed multiprotocol label switching (MPLS) networks. The technique operates directly on the optical signal without optoelectronic (O/E) conversion; therefore, it is bit-rate, label length, and protocol/format independent. Experimental results are presented for the label swapping of distinct 8-b-long labels in a system with 2 WDM data channels at 10 Gb/s. There is a guard time of 400 ps between the payload and the label. The power penalty introduced by the method is less than 3 dB. This method can potentially accommodate 10 WDM channels simultaneously over the PPLN waveguide´s ∼40 nm λ-shifting bandwidth.