Graphene-Assisted Multiwavelength Erbium-Doped Fiber Ring Laser

We propose and experimentally demonstrate a stable multiwavelength erbium-doped fiber (EDF) ring laser based on four-wave-mixing of atomic few-layer graphene. The compact laser cavity consists of 3-m EDF, an optically deposited ultrathin graphene device, and a polarization-maintaining fiber Sagnac loop filter. The comparison between the ring laser cavity without and with the graphene device shows that the highly nonlinear graphene can be helpful to mitigate the mode competition of EDF laser and stabilize the multiwavelength oscillation. Under the assistance of the graphene device, power-equalized eleven-channel simultaneous lasing with a wavelength-spacing of 0.54 nm is achieved at room temperature. This laser has a very high extinction ratio up to 57 dB and a narrow linewidth per channel of less than 0.01 nm.