Modal analysis and device considerations of thin high index dielectric overlay slab waveguides

Abstract

The effect of adding a thin high index dielectric overlay layer onto a 3-layer slab waveguide demonstrates several interesting features that can be exploited in integrated optical device configurations. A simple modal analysis is employed to examine the behavior of guided light launched from a 3-layer waveguide structure then coupled and propagated in the 4-layer overlay region. Modal properties typically overlooked in conventional slab waveguides are made use of in the design and theoretical analysis of an MMI device and optical index of refraction sensor. The optical structure presented here can form the backdrop waveguide design for more complex and active devices.

Spectral coupling of elements of integrated optical devices based on chalcogenide glasses

“…This was done using the transfer coefficient characterizing the power fraction remaining in the waveguide mode when it enters the four-layer region provided that losses are possible only due to non-coincidence of the mode profiles. The transfer coefficient was calculated using the overlap integral of the profiles of modes of the three-and four-layer waveguide regions [6].…”

“…In the extreme regions, one can observe mode beatings [6] caused by multimode interference [7]. In a particular case, when the initial three-layer waveguide is single-mode, the four-layer region of the structure becomes multimode with increasing thickness of the upper layer.…”

A novel beam splitter based on graded photonic crystals

“…[3][4][5][6][7][8][9] Beam-splitting structures are the key building blocks in optical integration devices, so numerous beam-splitting structures based on PCs have been presented. [10][11][12][13][14][15][16][17][18][19][20][21][22] Several methods have been studied to realize the beam-splitting phenomenon, including photonic band gap, 10,19,20 directional coupling, 11,14,15 defects 12 and self-collimation. 13,16,17 However, the splitting efficiencies achieved by these methods are low, and the splitting ratio cannot be changed discretionarily.…”

Integrated optic platform for photonic crystal devices

“…This section introduces the novel use o f multimode thin high dielectric overlay slab waveguide structures for integrated optics as published and presented in concert with this work. [60,61] The coupling o f light to the platform and its capability for devices are covered. In order to explore the structures, modal modeling methods are used alongside FDTD.…”

“…This appendix examines several structures o f interest that were discovered alongside the main body o f this work. [60,61] In the m ultimode discussion in section 3.2, it is discovered that it is possible to have the effective index o f a 3 layer mode and a 4 layer mode match. This results in the field profile o f the fundamental mode o f the 3 layer waveguide overlapping exactly for exceptional coupling in the substrate and waveguide regions with the field profile o f the second mode when the overlay is added.…”