Terahertz wavelength conversion based on four-wave mixing in λ/4-shifted DFB lasers:: Dynamic range and performance analysis

By using coupled mode equations, the characteristic of terahertz wavelength converter based on four-wave mixing in lambda/4-shifted distributed feedback lasers is analyzed. The numerical simulation indicates that, the larger biasing current and smaller detuning can expand the dynamic range of conversion efficiency and extinction ratio, but worsen the frequency chirp. Due to the lasing effect, the peak modulation frequency of extinction ratio and frequency chirp occurs at relaxation oscillation frequency. The good conversion characteristic can be obtained by selecting system parameters reasonably. This configuration could have potentials in optical communications because of wideband, high-speed, and no need for pump input.