Wavelength-spacing tunable multi-wavelength erbium-doped fiber laser incorporating a semiconductor optical amplifier

A multi-wavelength erbium-doped fiber laser incorporating an semiconductor optical amplifier (SOA) based on a tunable Mach-Zehnder interferometer (as a comb filter) is proposed. Wavelength-spacing can be continuously tuned and multi-wavelength lasing with wavelength spacing of 0.4 nm, 0.8 nm, and 1.6 nm is demonstrated. The output of the proposed multi-wavelength laser is rather stable at room temperature and the output spectra can be adjusted by controlling the bias current of the SOA and the power of the pump laser diode.