Progress in wavelength conversion by difference-frequency generation in AlGaAs waveguides

Significant technological progress in wavelength conversion by difference-frequency-generation (DFG) has taken place since its conception for wavelength-division-multiplexing (WDM) network applications in 1991. This paper reviews progress in wavelength conversion by DFG in AlGaAs waveguides and discusses its implications for WDM network applications. The measured conversion efficiency versus the input wavelength is shown for two input polarizations. An extremely broad tuning curve is demonstrated with /spl sim/90 nm bandwidth and a polarization independent conversion process. Simultaneous conversion of 17 channels is also shown. Here, arbitrary input polarizations were used, and each channel achieves identical conversion efficiency. One of the important considerations for network applications is a requirement for an effective means to filter unwanted channels. One such method is based on polarization diversity, and a measured spectrum exploiting the unique polarization characteristics of the conversion process in an AlGaAs waveguide is also given.