Create a taper with angled sidewalls using planar solid structure

planarsolid
structuregroup
mode
fdtd
device

#1

In the Object Library you can find objects to construct tapers with vertical walls (Isosceles Trapezoid) and also for creating a straight waveguide with angled sidewalls (Straight Waveguide). For the “combination” of both structures, a taper with angled sidewalls, you can use define a planar solid structure inside a structure group, as in the attached example file taper_angled_sidewall.fsp (236.6 KB).

In order to define the planar solid structure it is necessary to specify the position of the vertices as shown below. The order in which the vertices are listed defines the labels when defining the sets of points that form each of the facets.

The labels of the vertices are shown in the image below, together with a front view of the taper. The parameters used to define the geometry of the taper are also shown.


How to generate a tapered waveguide with custom cross section?
Polygon和Planarsolid的区别及其应用
#2

Import from GDS
This structure group allows users to draw the linear taper with sidewall angle by defining the widths, height. and sidewall angle. It is also possible to import the taper from a GDS file and extract the taper parameters to feed this structure group. Here is an simple example:

import_taper.lsf (771 Bytes)
taper_test.gds (322 Bytes)
taper_angled_sidewall_generalized_KX.fsp (228.6 KB)

Taper orientation
The imported taper (GDS_LAYER_1) is assumed xy plane and y propagation. For a different propagation direction, edit the definition of the width accordinly in the lsf file.

The taper with a sidewall angle is assumed xy plane and x propagation. For a different plane or propagation direction, make use of the options under the Rotations tab of the structure group.

Viewing the taper object
Since the taper is usually an elongated object with a large aspect ratio, the CAD may not by default have the best aspect ratio set to easily show the taper. It is useful to use to Zoom Extent feature to adjust the aspect ratio for viewing. Hotkey: keyboard X