A wavelength selective add-drop multiplexer utilizing a directional coupler loaded with a first order Bragg grating can be
realized both in fiber and planar technologies. Specifically for the planar case, we detail a systematic design procedure
leading from general assumptions concerning the functional parameters of the device down to geometrical dimensions of
the resulting planar microstructure. The functional parameters include: channel spectral width and channel isolation. The
resulting dimensions are: waveguides etch depth, grating etch depth and lengths of apodized-grating trenches. Grating
apodization profile of the form sin^n is assumed. Design curves are presented, enabling an optimal choice of the
apodization profile's exponent n considering a tradeoff between the required channel isolation and the resulting grating
length.
We present results of numerical modeling of photonic crystal (PhC) structures fabricated in gallium nitride (GaN). GaN
is a wide band gap semiconductor material with large refractive index and very good thermal and mechanical properties,
so it is considered a valuable candidate for photonic crystal application - in particular for devices exposed to the harsh
environment. In this paper are considered the ideal 2D PhC with infinite high for a different lattice structures and
calculated optical band gap maps for each. We also calculated air-bridge type slab and "sandwich-type" PhC slabs with
finite height. The dependence of transmission and reflection spectra on holes size, width and profile of "sandwich-type"
PhC slab structure are investigated. All calculations were performed using plane wave expansion method (PWE) and
finite difference time domain method (FDTD).
Gallium nitride is an important material for the contemporary optoelectronics. Large electric band gap, high temperature
resistivity and environmental resistance make GaN interesting also for sensor applications. However, asymmetric
structure of GaN-on-sapphire slab waveguide, grown as a conventional epitaxial heterostructure, poses a problem with
achieving high quality (Q) factor resonators. In this paper, issues related to an asymmetric structure of a waveguide and
theoretical possibilities to achieve high Q-factor resonator in the GaN planar structures are discussed. Three dimensional
(3-D) finite-difference time-domain (FDTD) modeling tools were used. It is shown that the highest Q-factor value of
~ 23 000 is obtained for a symmetrical membrane in L9 (nine points-defect cavity) micro-cavity based on GaN planar
waveguide. In reference to the simulation results, we also discuss the technological issues, i.e. fabrication of photonic
crystal patterns in GaN layers. New approach presented here included deep RIE etching with use of only single masking
layer and conductive polymer usage in e-beam pattering. Possible applications of the micro-resonators for sensor
applications are discussed.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.