Dual-Wavelength Single-Longitudinal-Mode Polarization-Maintaining Fiber Laser and Its Application in Microwave Generation

A novel approach for generating high-frequency microwave signals is proposed and experimentally demonstrated. With a pair of wavelength matched fiber Bragg gratings written directly in a polarization-maintaining erbium-doped fiber, a stable short cavity dual-wavelength single-longitudinal-mode (DW-SLM) distributed-Bragg-reflector fiber laser with orthogonal oscillation modes is realized at room temperature. The wavelength spacing between the two lasing modes is 0.374 nm. By heterodyning the two wavelengths of the DW-SLM fiber laser at a photodetector, microwave signal at over 46 GHz is achieved.