Generation of terahertz signal by photomixing Kelly sidebands of mode locking fiber laser

Abstract

We investigate the photomixing Kelly sidebands of soliton mode-locking fiber laser to generate the Terahertz (THz) signal. A simulation model about soliton fiber laser with obvious ±1 order Kelly sidebands is built up to design the sidebands with strong intensity, narrow bandwidth and adjustable spacing. It is found that the parameters of mode-locking fiber laser such as the total dispersion, filtering bandwidths, pump power of the laser play significant roles in determining the features of the ±1 order Kelly sidebands and the relationships between them are investigated. By photomixing the ±1 order sidebands, the experimental result shows that the desired THz signals with high optical-to-THz conversion are generated at frequencies of 0.187THz from the lab-made Yb-doped mode-locking fiber lasers. Well-designed Er-doped ring-cavity soliton fiber laser is used for obtaining THz signal of narrow linewidth with 1.35THz frequency tunable range.