Dual-wavelength f iber grating laser in linear overlapping cavity

We report a switchable dual-wavelength fiber grating laser in linear overlapping cavity.The laser features two overlapping cavities sharing a single Yb-doped gain medium fiber and two sets of fiber Bragg gratings.A coiling fiber setup is inserted into the 1035 nm laser cavity.Given that the bending loss is inversely related to the bending radius,the cavity loss of 1035-nm can be modulated.Modulating the bending loss facilitates the switching of the fiber grating laser to a single-or dual-wavelength output at 1030 or 1035nm and convenient tuning of the power ratio of the two wavelengths.An approximately 152.6-mW output power and up to 38-dB polarization extinction ratio are observed.The simultaneous lasing at 1030 and1035 nm is a qualif ied seeder source for amplif ication to high power scale and can be applied to dif ference frequency generation of a terahertz signal.This dual-wavelength fiber grating laser is a potential pump source for generating terahertz radiation using a novel approach.