Switchable dual-wavelength SLM narrow linewidth fiber laser based on nonlinear amplifying loop mirror

Abstract

We demonstrate a stable switchable dual-wavelength single longitudinal mode (SLM) narrow linewidth ytterbium-doped fiber (YDF) laser using a nonlinear amplifying fiber loop mirror (NALM) at 1064nm. The NALM of intensity-dependent transmission acts as a saturable absorber filter and an amplitude equalizer to suppress mode competition and the fiber Bragg grating (FBG) pair is used as one wavelength selection component. By properly adjusting the polarization controllers (PCs), the switchable dual-wavelength SLM fiber laser can be operated steadily at room temperature. The optical signal-to-noise ratio (OSNR) is better than 50dB for both lasing wavelengths. Meanwhile, the linewidth of the fiber laser for each wavelength is approximate 17.07kHz and 18.64kHz with a 20dB linewidth, which means the laser linewidth is approximate 853Hz and 932Hz FWHM. Correspondingly, the measured relative intensity noise (RIN) is less than −120dB/Hz at frequencies over 5.0MHz.