Tight-Binding Theory for Coupling of Identical Photonic Crystal Waveguides and its application for Wavelength-Division Multiplexing design

• Main Author: 涂家斌
• Other Authors: 謝文峰
• Format: Others
• Language: en_US
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/32179890911221797360

碩士 === 國立交通大學 === 光電工程系所 === 93 === By using tight-binding theory of solid-state physics, we can analytically describe the dispersion relation of the propagation in a photonic crystal waveguide (PCW). In turn, we can derive the dispersion curves of two coupled identical PCWs . Due to not only the transverse coupling as the conventional coupled waveguides but also the longitudinal coupling of two coupled identical PCWs. “Band-crossing” may occur at which the PCWs will not couple with each other (or decoupled) when the coupled PCWs are placed close enough to each other. By employing the tight-binding theory to this problem, we can accurately determine the decoupling frequency as well as calculate the coupling length for every frequency. We have designed a wavelength division multiplexer which can route three wavelengths into different channels with the power ratio of all outputs reach 20 dB, the specification of optical communication.