Multiwavelength Fiber Ring Laser Source Incorporating a Sagnac interferometer

A fiber ring laser which uses a fiber Bragg grating for switchable multiwavelength operation is proposed. Only by adjusting the polarization controller, the laser can be switched stably and repeatedly in the single-, dual-wavelength lasing operations. Due to the introduction of Sagnac interferometer, the output spectra are more stable. Experimental results show that the stable dual-wavelength lasing operation with a wavelength separation of 0.245 nm can be achieved at room temperature and triple-wavelength lasing with wavelength separation of 0.262 nm and 0.150 nm. The configuration is simple and flexible.