Multiwavelength tunable fiber ring laser based on sampled chirp fiber Bragg grating

We propose and experimentally demonstrate a novel configuration of a multiwavelength tunable fiber ring laser with equally increased or decreased wavelength spacing. Wavelength tuning is achieved by tuning the strain gradient of a sampled chirp fiber Bragg grating (SCFBG), which is integrated in the laser cavity. To achieve equally increased or decreased wavelength spacing, the SCFBG is surface-mounted at a slant onto one lateral side of a plate so that each wavelength-selective element of the SCFBG will experience an equal strain increment when an external force is applied to the plate. We experimentally obtain seven lasing wavelengths with equally increased or decreased wavelength spacing.