# Spirals¶

Spirals are useful components to insert large waveguides on a small area. In Picazzo there are three different kinds of spirals

• SingleSpirals have a input port inside the spiral and an output port outside the spiral.
• DoubleSpirals have both ports outside the spiral.
• DoubleSpiralsWithInCoupling have both ports outside the spiral with in coupling waveguides.
• FixedLengthSpiral is a double spiral with in coupling sections with a fixed length that can explicitly be set.

All spirals can also be rounded for which there are specialty classes as well.

 SingleSpiral Single spiral class going from the inside to the outside. SingleSpiralRounded Rounded single spiral class going from the inside to the outside. DoubleSpiral Double spiral class with both access waveguides on the outside of the spiral. DoubleSpiralRounded Rounded double spiral class with both access waveguides on the outside of the spiral. The trace template provided in the property trace_template is used to build a chain of waveguides. DoubleSpiralWithInCoupling Double spiral class with both access waveguides on the outside of the spiral. DoubleSpiralWithInCouplingRounded Rounded double spiral class with both access waveguides on the outside of the spiral. FixedLengthSpiral Spiral with incoupling sections that calculates its length. FixedLengthSpiralRounded Rounded spiral with incoupling sections that calculates its length.