A fiber laser with a comb-like spectrum

An unpolarized comb-like spectrum is emitted from a fiber laser constructed from a Nd-doped silica fiber connected to an undoped high-birefringence fiber. Depending on the overall birefringence of the high-birefringence fiber, spectral spacings of 0.8 nm to 4 nm between two adjacent wavelengths were obtained, with as many as eight simultaneous discrete peaks. No intracavity polarizing elements were used, and the observed spectral characteristics are due to parasitic reflections at the interface between the two fibers.<
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