Multiwavelength Single-Longitudinal-Mode Ytterbium-Doped Fiber Laser

We demonstrate a multiwavelength single-longitudinal-mode (SLM) ytterbium-doped fiber laser. Two Sagnac loop mirrors are inserted into the cavity to ensure multiwavelength and SLM operation, respectively. Three wavelengths with a wavelength spacing of 1.8 nm are generated under stable operation, and the linewidth of each wavelength is measured to be narrower than 100 kHz. A side-mode suppression ratio of greater than 56 dB is achieved for each wavelength. The maximum power fluctuation was less than 0.8 dB for each wavelength. This scheme has the potential to be employed as a useful source in optical communications, fiber optical sensing, and high resolution spectroscopy in the 1-μm wavelength band.