Optical filters with use of optical waveguide bends

Abstract

Use of fiber lightguides as directing systems is caused by performance of total reflection conditions. One of conditions is excess of critical value of the hade. Thus, the critical angle is defined with respect to refractive index of the core and cover of fiber lightguide. In such cases, fiber transfer constant becomes dependent on wavelength, and optical fiber acquires filtering properties. One of the factor for determining presence of dispersion in the cover is the fiber bends. The usage of optical fiber bends to solve the tasks of optical signals filtration is of interest. Transfer characteristics of planar optical waveguide sections containing a bend are investigated in the offered work. The researches were carried out in the range of wavelengths 0,8-1,6 mkm. Thus, the dependence of the refraction index on wavelength was described by the Sellmeier's formula. The method of losses account on the optical waveguide bends, was used to define transfer characteristics. Calculations were carried out for optical waveguides consisting of different kinds of the optical glass. The results of calculations prove the presence of transmission characteristics dependence of optical waveguide bends on wavelength. This fact can successfully be used for creation of optical filters by choice of glass structure, radius and number of bends. The search and synthesis of new glass structures is of interest for this purpose.