Tunable single-frequency erbium-doped fiber ring laser for microwave photonics applications

We propose and demonstrate a novel wavelength tunable single-frequency erbium-doped fiber ring laser. The single-frequency operation is realized by using a coupler loop mirror with an Er/sup 3+/-doped fiber saturable absorber, which acts as a narrow band optical filter. The fiber laser can find applications in microwave photonics systems.