Reply To: Euler bend pins extend further or inside waveguide

[Ronald]

Dear Lumico,

This is the same/similar effect as the snapping discussed in this post.
The delta is in the order of the grid resolution or smaller.

The simplest way to align the pin with the end line is to add a polygon point to the waveguide at the pin location. This is something that may be added to Nazca, mainly to avoid this visual misalignment (mostly harmless). Note this phenomena is not specific for the Euler bends but something that tends to show up for floating point positioning and subsequent snapping to a grid.

The above is optically and process-technically mostly not an issue, but floating point rotations and/or translations in combination with hierarchical (gds) design can lead to (grid resolution) notches after flattening a design for mask manufacturing. In silicon photonics the DRC tends to be relatively unforgiven and it flags these notches (they can be waived, typically). The reason is that these DRC rules are based on previously existing “multiples of 90 deg” kind of geometries and not on photonic floating point geometry. In Nazca we created methods that force cells to ultimately snap polygons to the same top cell grid. These are not in the public Nazca release branch at present.

Ronald