Fujitsu Laboratories and the Fraunhofer Heinrich Hertz Institute HHI have developed a new method to simultaneously convert the wavelengths of wavelength-division-multiplexed signals. The researchers have successfully tested the method using high-bandwidth signal transmission in the range of 1 Tbps.
Conventionally, optical wavelength conversion has worked by converting each individual optical wavelength into an electrical signal that is then re-transmitted at a new wavelength. The researchers said this method is proving impractical for terabit-class processing, as each wavelength requires its own O/E/O circuit.
Using the new methos, the optical wavelength conversion and the polarization state are controlled at the same time, so simultaneous wavelength conversion of wide-band optical signals can be achieved without restrictions on the wavelengths of the optical input signal or the modulation formats. As a result, processing can be achieved with a single wavelength converter, regardless of the number of wavelengths multiplexed. Therefore, considering optical signals in excess of 1 Tbps multiplexed from ten wavelengths, for example, the new method can process them using just one-tenth of the power or less compared to previous technologies that required a separate circuit to convert each wavelength into an electrical signal and back.
