Single modulator payload/label encoding and node operations for optical label switching

We present and analyze payload/label encoding based on a single Mach-Zehnder modulator, in which the payload is differential phase-shift keyed and the label is amplitude-shift keyed through modulation of either the modulator bias or the amplifier gain. The encoding is analyzed numerically and experimentally. Simultaneous encoding of a 10-Gb/s payload and a 155-Mb/s label is demonstrated with high receiver sensitivities. Penalty-free transmission over 80 km of standard single-mode fiber is achieved for both the payload (with dispersion compensation) and the label (without dispersion compensation). Furthermore, polarization-independent label processing and payload wavelength conversion at intermediate nodes are proposed for potentially cost-effective node operations.