Demultiplexing and routing of TDM signal using wavelength conversion by four-wave mixing and wavelength routing by fiber gratings

Using wavelength conversion by four-wave mixing, and wavelength routing by a combination of fiber gratings and optical circulator, demultiplexing and routing of 10 Gb/s (= 2.5 Gb/s × 4) TDM optical signal were accomplished. After synchronizing and mixing each channel of the multichannel TDM signal with the multiwavelength control optical pulse, the wavelength of each channel of the TDM signal was converted to a different wavelength using four-wave mixing in the dispersion-shifted fiber. The phase matching condition can be satisfied by setting the signal wavelength at zero-dispersion wavelength. After wavelength conversion, the optical signal was led to the wavelength router with multiple fiber gratings and optical circulator. Then, signals with different wavelengths were observed at different ports. Using apodised fiber gratings, sidelobes were suppressed to improve the wavelength selectability. As a result, the channel-to-channel crosstalk was below -25 dB.