Dual Bragg grating frequency stabilization of a 980 nm diode laser

In this paper we present a robust approach to Bragg grating stabilization of diode lasers which utilizes two FBG´s matched in wavelength, bandwidth, and reflectivity. These two FBG´s in the fiber pigtail form a third cavity to the laser system The functionality of the dual grating cavity is to reduce the coherence of the laser light reflected from the cavity through Fabry-Perot interference. This allows the location of the entire FBG cavity to be within the coherence length of the diode laser and still obtain stable multi-mode coherence collapse operation.