Multiwavelength erbium-doped fiber laser based on frequency shift and polarization hole burning

For realizing a stable multiwavelength erbium-doped fiber laser at room temperature,sinusoidal phase modulation and polarization hole burning are introduced in the laser cavity to suppress the mode competition.In the linear cavity,a semiconductor optical waveguide is used as a reflective mirror,and driven by a sinusoidal signal.The semiconductor waveguide can be classified here as two optical devices:a sinusoidal phase modulator and a nonlinear phase retarder.The sinusoidal phase modulator produces frequency shift for the fiber laser,and the nonlinear phase retarder introduces polarization hole burning in the erbium-doped fiber.Stable lasing with multiple wavelengths up to 10 and wavelength spacing of 0.32nm was demonstrated at room temperature.The power fluctuation was less than 3dB.The results that the phase modulation and polarization hole burning is propitious to suppress the mode competition owing to the homogeneous broaden line.