Tuning, selecting and switching wavelengths in lasers with chirped and sampled fiber Bragg gratings by high-order mode-locking

We study wavelength selectable and switchable lasers with two kinds of fiber Bragg grating (FBG) reflectors, based on high harmonic mode-locking frequency addressing near 10 GHz and 25 GHz. We used fiber lasers and also show results with a cavity extended semiconductor laser. The first implementation of the tunable laser uses a chirped FBG. Different wavelengths define slightly different cavity lengths and an effective dispersion and a wavelength is selected by applying a corresponding mode-locking frequency. We obtained a ∼17 nm wavelength tuning range at the 1550 nm regime. We also summarize results with a cavity extended semiconductor laser by a chirped fiber grating that gave stable 28 addressable and switchable wavelength channels with a spacing of 100 GHz (≈0.8 nm). Here we obtained a tuning range of ∼22.4 nm at the 1550 nm wavelength regime. The second implementation uses multiple sampled FBGs with different reflecting wavelengths, each determines a different cavity length and therefore a different modulation frequency.