A switchable dual-wavelength erbium-doped fiber laser is proposed. The proposed fiber laser, which utilizes a two-taper
Mach-Zehnder interferometer filter as the wavelength-selective component, realizes single-, dual-wavelength switching
by adjusting the curvature of two-taper. The side-mode suppression ratios (SMSRs) is over 36 dB and the power
variation for each wavelength is less than 0.5dB in one hour under room temperature.