Tunable and interval-adjustable multi-wavelength erbium-doped fiber laser based on cascaded filters with the assistance of NPR

•A tunable and interval-adjustable EDFL based on the cascaded filters is reported.•The number of output wavelengths can be 1–7, and the OSNR can up to 47 dB.•The output wavelengths can be tuned with the range that more than 18 nm.•The outputs can achieve changes in wavelength interval by adjusting PCs.