We have proposed and implemented an all-polarization-maintaining modelocked fiber laser operating in all-normal-dispersion regime based on nonlinear amplifying loop mirror. The required spectral filtering on the circulating chirped pulse was realized with a Lyot filter that was constructed by two carefully angle-spliced polarization-maintaining single-mode fibers within the laser resonator. The intrinsic inline fiber optical filter exhibited desirable features such as compact layout, adjustable

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... versatility, and long-term stability. By changing the specific fiber length, our laser could deliver pulses with spectral bandwidth from 0.5 to ∼4 nm. Furthermore, a continuously tunable single-wavelength operation and an asynchronous dual-wavelength operation can both be obtained with the laser setup including an improved Lyot filter, and the experimental observations agreed well with numerical analysis.