Calculation of Mode-Coupling Coefficient of Symmetric/Asymmetric Waveguide Grating Structure

Vol.1 No. 1

Year: 2010

Issue: Sep-Nov

Title: Calculation of Mode-Coupling Coefficient of Symmetric/Asymmetric Waveguide Grating Structure 

Author Name: S. K. Raghuwanshi, V. Kumar, Radha Raman Pandey 

Synopsis:

A “Bragg Grating is a periodic perturbation of the effective absorption coefficient or effective index of an optical wave guide. A fiber Bragg grating (FBG) is a type of distributed Bragg reflector constructed in a short segment of optical fiber that reflects particular wavelength of light and transmits all others. This is achieved by adding a periodic variation to the refractive index of the fiber core. Several devices for wavelength division multiplexing (WDM) systems which utilize mode conversion in waveguides have been proposed and demonstrated. This paper demonstrates the calculation on mode coupling coefficient for the case of planar waveguide structures. We have carried out the computation for the mode coupling coefficient for the cases of degenerate as well as non-degenerate mode. Finally the interpretation of the results is carried out. The performance of FBG due to waveguide structure is predicted. We have to use FBG as a WDM component to accommodate the more number of channels. For this application we need to increase the reflection bandwidth of the reflectivity spectrum. We are also required to reduce the chirp induced in the phase spectrum due to mode coupling.  These all the performance parameters depend on the mode coupling coefficient. Hence; we try to optimize the coupling coefficient for the given cases. Finally the quantitative study has been carried out.