A Simple and General Analytical Expression for Calculating Crosstalk in Multiwaveguide Directional Couplers Using Finite Differences Method

Abstract

In optical communication systems, the main aim is to control and limit the unwanted Crosstalk (CT) effects on wavelength divisions multiplexing (WDM) channel, which degrade the transmission performance. To do this, a simple approximate formula was presented for calculating the CT of multiwaveguide directional coupler (DC) using Finite Differences (FD) method. Through this formula, the input power can be controlled to be entered from one specified channel, which is required in some applications. Then, the evolution of the power has been determined without using Beam Propagation Method (BPM). The purpose of this paper is to calculate the CT for arbitrary input channel. Result obtained from this formula are in a complete agreement with the previous works for two and three waveguide directional couplers.

Keywords

• Mach-Zehnder Interferometer
• Dense Wavelength Division
• Multiplexing
• Crosstalk
• Normal mode theory