Design and simulation of periodic dielectric waveguide splitter

• Main Author: Ng, Kah Sheng.
• Other Authors: Liu Aiqun
• Format: Final Year Project
• Language: English
• Published: 2010
• Subjects: DRNTU::Engineering::Electrical and electronic engineering::Antennas, wave guides, microwaves, radar, radio
• Online Access: http://hdl.handle.net/10356/40851
• Institution: Nanyang Technological University

Photonic Crystal (PC) has always being an essential unit in design of optical devices and also in photonic integrated circuit. However, there are several disadvantages in using PC which will affect its output and also during fabrication. These problems can be solved using Periodic Dielectric waveguide. Periodic Dielectric waveguide (PDWG) is formed by aligning a sequence of dielectric rods in air to form a 1 X 2 beam splitter. The beam splitter is made to be able to be tunable in term of power outputs at both output ports. Finite difference time domain (FDTD) method is used to calculate the band structure for the guided mode in PDWG. Three types of modes are being investigated during this simulation, single mode, dual mode and quadruple mode. During simulation, it is found that single mode beam splitter do not carry the ability to provide tunable outputs and quadruple mode beam splitter produce excess losses, dual mode beam splitter meanwhile, have the best results. It is also found that when operate in the correct frequencies, PDWG is observed to have high transmission (above 90%). For a beam splitter, the bends is the most critical part of the structure, because of PDWG flexibility, different bends is possible to be achieved. Three types of bends is being investigated here, 90° bend, Y-Shaped and S-Shaped. The simulation results show that Y-Shaped is the worst performer of the three while the 90° bend is produce the best result.