Switchable high-stability dual-wavelength fiber laser based on seven-core fiber

Abstract A dual-wavelength switchable and high-stability erbium-doped fiber laser (EDFL) based on a seven-core fiber Mach–Zehnder interferometer (MZI) is proposed. The MZI is constructed by fusing a segment of seven-core fiber (SCF) between two segments of ordinary single-mode fiber through a bumpy taper shape node. By integrating this MZI to an EDFL loop, stable and high optical signal-to-noise ratio (OSNR) single-wavelength and dual-wavelength outputs can be obtained, and the output can be switched between single-wavelength and dual-wavelength by adjusting the polarization controller. The OSNR of the output spectrum is greater than 48 dB. In addition, the laser has high stability, with a maximum wavelength drift of 0.14 nm and a power fluctuation of less than 0.6 dB over a test time of 180 min.