A switchable and tunable dual-wavelength linear cavity erbium-doped fiber laser based on a single fiber Bragg grating (FBG) written on standard single-mode fiber is demonstrated experimentally. It exploits the birefringence characteristic of the FBG when submitted to transverse strain. By simple adjustment of a polarization controller (PC), the proposed laser can operate in stable dual-wavelength or switch between two wavelengths, all at room temperature. Transverse strain on the FBG induces spacing between the two emitting wavelengths while axial strain shifts both wavelengths together.