THE DIRECTIONAL OPTICAL COUPLER BASED ON ANISOTROPIC OPTICAL FIBER

Abstract

The paper presents the results of the development of the design of a directional coupler of a fiber-optic transmission system of a new type, which provides spatial separation of optical signals with different working wavelengths or power separation of an optical signal of the same wavelength. The operation of this device is based on the features of the electromagnetic coupling between anisotropic optical fiber and isotropic stepped single-mode optical fiber. As an anisotropic optical fiber, a fiber with an ordered rotational microstructure of glass was selected. In the article equations were used that relate the chemi-cal compositions of the cores and shells of the optical fiber, the parameters of the ordered rotational glass microstructure, the powers of the optical signals that pass from the anisotropic fiber to the isotropic optical fiber, and the working wavelengths of optical signals. The lengths of fiber sections are also de-termined, where it is necessary to arrange them in parallel, depending on the part of the power that needs to be transferred from anisotropic to isotropic optical fiber. Since there is an equality of phase wave propagation coefficients (achieved by selecting the required step of rotation of the microstructure of glass), the condition for the transition of an electromagnetic wave from an anisotropic fiber to an iso-tropic optical fiber one is satisfied. The resulting spectral analysis proves the possibility of realizing de-vices that can be used on a passive optical network to separate optical signals with different working wavelengths or to divide the power of an optical signal of the same wavelength.