Dual-Wavelength DFB Fiber Laser Based on Unequalized Phase Shifts

A novel structure for dual-wavelength distributed feedback (DFB) fiber laser is proposed and experimentally demonstrated. This structure is based on a uniform fiber Bragg grating with two unequalized phase shifts, which markedly suppress the mode competition of the two lasing wavelengths; and then a 52-pm-spaced dual-wavelength DFB fiber laser operating at single-longitudinal-mode and single-polarization is achieved at room temperature. A simple method is also implemented to fabricate the phase shifts with high precision.