I. Introduction
HIGH-capacity all-optical networks based on optical time division multiplexing (OTDM) and wavelength division multiplexing (WDM) require compact and stable switching devices, for example for high-speed demultiplexing and add–drop multiplexing [1] [2]–[5]. Many high-speed demultiplexing methods and devices have been demonstrated, such as cross-phase modulation (XPM), in a nonlinear optical loop mirror (NOLM) [2], semiconductor optical amplifier (SOA), Mach–Zehnder interferometer (MZI), or Michelson interferometer [3], [4], four-wave mixing in a dispersion shifted fiber (DSF), or an SOA [5] and electroabsorption (EA) modulator. Using these demultiplexing methods, the degradation of signal quality due to noise accumulation, pulse distortion, and crosstalk cannot be effectively suppressed. All-optical 2R regeneration based on the effect of self-phase modulation (SPM) of the data signal in a dispersion shifted fiber has been demonstrated [6]. This method suppresses the noise in 0 bits and the amplitude fluctuations in 1-bits of return-to-zero (RZ) optical data streams. Use of XPM with subsequent filtering to realize wavelength conversion was reported in [7]; recently 40-Gb/s wavelength conversion was realized by using this method [8]. In this paper, based on the two methods of [6] and [7], we present a new method that has the function of simultaneous demultiplexing and regeneration. The method is based on the effects of XPM and SPM in a dispersion shifted fiber after subsequent optical filtering demultiplexing and regeneration are realized simultaneously.