SLIDE 1-Opening slideGood evening ladies and gentlemen, my name
is arviza from UI and I would like to present you about design of
GaN based S-Bend Y-Branch power splitter with MMI structure.
SLIDE 2-presentation outlineHere is the outline, first , I want
to talk about GaN Material, Second, the BPM theory which is used in
OptiBPM, then about process to design power splitter and the last
is about the result of the simulations in this work.SLIDE
3-Introduction to GaNRecently GaN has attracted many researcher
because of its superior properties, such as: wide band gap which
means only few absorptions in IR region, has temperature stability
in extreme condition which is requirement for high power device,
the most enviromental friendly comparing to III-V compounds.As far
as we know, many research work using GaN material, such as: LD,
LED, etc. But only a few researcher who research about waveguide
based device using GaN, therefore, this situation motivate us to
design GaN based power splitter. The function of Power splitter is
to split light into several branches and can be used in
telecommunication device to bring information from one system to
another system. In this work, to simulate the design we use OptiBPM
12SLIDE 4-BPM TheoryTo simulate the design, OPtiBPM use FFTBPM to
calculate propagation of light in 3D, as you can see here, these
are 3 equation of FFTBPMSLIDE 5-design define materialFirst step in
designing power splitter is defining the material, In this work, we
use parameter GaN on sapphire from previous research who has
already done by TU Darmstadt, This is the composition, it consist
of sapphire, AlN low temp and High Temp, AlN/GaN, GaN. There is
several layer that we called Buffer layer Between top GaN layer and
Sapphire, it is used to reduce mismatch lattice between GaN and
Sapphire
SLIDE 6-design size of waferThe next step is defining size of
wafer, the length of the wafer is 1000 um and the width is 70
umSLIDE 7 dan 8- width and thicknessTo obtain the optimum size of
the waveguide, we did many simulations, it is shown that the
optimum size of Waveguide is 4 um length and 4 um width.SLIDE
9-type of wvThere are many type of waveguides but in this work, we
only use linear wv, rectangular waveguide as MMI and S-Bend
waveguide, MMI waveguide is used as transition to split mode from
single mode into two separating mode. S-Bend is used because it is
low loss and has S shaped structure which can make shorter device
comparing to Y linear junction, therefore the fabrication is
easier.
SLIDE 10-MMI designThe next step is we combine the linear
waveguide with the rectangular waveguide, the width of MMI is 8 um
to split two separating waveguide and we did simulation to obtain
the optimum length of waveguide and the result is 25 um.
SLIDE 11 s-bend designNext step, we combine S-bend with previous
simulation, we use s-bend cosine and did many simulation to obtain
the optimum radius of the s-bend, the optimum radius is 25 um,
SLIDE 12-final designThis is the final design in this work, SLIDE
13-relative powerAs you can see here, this is the power relative
output, starting from 0 um to 600 um in z-axis direction, the power
is maximum 100 %, start from 600 um to 1000 um, the power decrease
almost linearly to 94,5 %, this means that the losses only occured
in the S-Bend waveguide, we believe this happen because at bending
waveguide, the light field is pressed slightly to the outer core
cladding interface and deformed from its original profile, however
it can be reduced by adding offset. SLIDE 14-optical power
distribution Here is the optical power distribution of our power
splitter, the red color indicates 100 % of power and the yellow
color shown on s-bend waveguide, the shape of mode in the input,
MMI and output are shown around the picture, the form is uniform
and in the MMI structure the mode is widen.
SLIDE 15-CONCLUSIONFrom the simulation, it can be concluded that
the size of straight waveguide is 4 um for both length and width,
the size of MMI 25 um for its length and 8 um for its width and the
optimum radius of S-bend is 10,5 um, thats all, thank you
