Dynamic Interferometer based on Fiber-Bragg-Grating Laser Diode

A dynamic interferometer based on the fiber-Bragg -grating laser diode (FBG-LD) is proposed in this paper. The theoretical model of the FBG-LD base on the mode-structure model of the external cavity lasers is established, illustrating that the mode hopping probability lowers with the decreased reflectivity of the chip AR end. The random wavelength hopping of 10-2 pm level of the FBG-LD is observed, hardly influencing the dynamic interferometry, which is proven theoretically and experimentally. A Twyman-Green dynamic interferometer with the FBG-LD is constructed for the wavefront measurement of the triple-reflection system. According to the experimental results, it is clear that the interferogram contrast with FBG-LD is improved significantly in the extremely low reflectivity of 0.043.