When stringing multiple parts together, it is important to check a lightwave system for losses. BeamPROP Simulator, part of the Rsoft package will display any losses in a waveguide pathway. Here we have an example of an S-bend simulation. There appears to be losses in a few sections.

Here, the design for the S-bend waveguide has a few locations that are leaking, as indicated by the BeamPROP simulation.

The discontinuities are shown below, which are a possible source of loss:

After fixing these discontinuities, the waveguide can be simulated again using BeamPROP. In fact the losses are not fixed. This loss is called bending loss.

Bending loss is an important topic for wavguides and becomes critical in Photonic Integrated Circuits (PIC).