Minimum-phase reconstruction method for the determination of the specifications of FBGs

The fiber Bragg grating (FBG) design usually starts from the specification of the required spectral transfer function upon reflection. In a large number of applications, only the magnitude response of this transfer function is defined. However, in order to design any device, both the magnitude and the phase are required. In this paper, the well-known method of minimum-phase reconstruction is proposed to determine the phase response associated to a desired magnitude response, in order to define the specifications imposed over the synthesis tools of FBGs. This procedure enables the synthesis of a FBG device with the minimum possible length to achieve the target spectral magnitude response.