All-fiber Mach–Zehnder comb filter based on tapered fibers for wavelength switchable erbium-doped fiber lasers

Abstract A wavelength switchable erbium-doped fiber laser was constructed based on an all-fiber Mach–Zehnder interferometer (MZI) comb filter. The MZI consisted of a fiber with two tapers. An L-band erbium-doped fiber was used as the gain medium, and 1557.92, 1563.2, and 1568.06 nm single-wavelength and dual-wavelength switchable lasers at 1558, 1563.7, and 1570.2 nm were realized by adjusting the polarization controller. During scanning, the maxmin power fluctuations of single- and dual-wavelength lasing were 0.604 and 2.482 dB, respectively. The signal-to-noise ratio was >24.46 dB and the laser’s 3 dB linewidth was <0.39 nm.