Narrow-linewidth Q-switched DBR laser on Ytterbium-doped glass

In this paper, an integrated passively Q-switched DBR laser made in glass integrated optics technology is designed, fabricated and investigated. The laser, operating at 1030 nm wavelength, is formed by an ion-exchanged single mode waveguide realized in an Ytterbium doped phosphate glass. The feedback is provided by a DBR structure made of a Fiber Bragg Grating and a dielectric mirror. The Q-switched behavior is obtained by hybridizing the saturable absorber on the waveguides, so that it interacts with the evanescent part of the guided field. The saturable absorber we use is a bis(4-dimethylaminodithiobenzil)nickel (BDN) dye incorporated in a polymeric film. Using this structure, we were able to demonstrate a Q-switched operation for several BDN concentrations, allowing to vary the pulse duration and the repetition rate of the device. Moreover, we report a very narrow 372 MHz wide emission spectrum while in Q-switched regime.