# Reference design flow

This chapter describes the reference design flow for the Luceda PDK for ALUVIA, with its functionalities and tooling.

Several types of design actions and design intents are considered:

- Photonic IC circuit design based on pre-defined building blocks and subcircuits

- Photonic IC component design and exploration based on technology information

- Library management

The following tools are used in the reference design flow:

> Function | Tool | Versions supported
> --- | --- | ---
> Circuit layout | L-edit | 2019.x, 2020.x
> Waveguide routing | IPKISS | 3.9.1
> Subcircuit layout | IPKISS | 3.9.1
> L-Edit | 2019.x, 2020.x
> Component layout | IPKISS | 3.9.1
> Component simulation | IPKISS | 3.9.1
> CST Studio Suite (FDTD) | 2017, 2018
> FDTD Solutions (FDTD) |

Product licenses

- IPKISS is a product of Luceda Photonics. Circuit design and waveguide routing from L-Edit requires a Luceda Link for Siemens EDA license.

- L-Edit and Calibre are products of Mentor Graphics (Tanner), a Siemens company.

- CST Studio suite is a product of CST - Dassault Systèmes.

- FDTDSolutions is a product of Lumerical.

Software licenses have to be procured from the separate vendors.

## Circuit layout and routing

Circuit layout is performed from within L-Edit or from IPKISS python script, depending on the user’s preferences.

- Using Luceda Link for Siemens EDA, PDK pcells as well as customer-defined cells are available within the L-Edit environment. From the L-Edit GUI, components can be instantiated using drag-and-drop, components can be connected conveniently with waveguides and metal wiring can be done.

- Using IPKISS, the same PDK pcells as well as customer-defined cells are available and can be laid out into a circuit using Python scripting. IPKISS provides features for semi-automated waveguide routing including fanout bundles and other convenience functions.

## Component design

Component and subcircuit layout

User-defined components and subcircuits can be created in IPKISS python script and made available in the L-Edit design environment. IPKISS provides basic building block definition based on technology layers, as well as powerful macros for waveguide routing, device placement, fanouts, and so forth.

Component simulation

Optical (electromagnetic) simulation of devices can be managed with IPKISS. IPKISS provides a built-in 2D mode solver and propagation tool. For more accurate simulations, CST Studio Suite as well as Lumerical FDTD Solutions can be driven in a semi-automated and reproducible way. The simulation results can directly be imported in IPKISS and used as a compact model in the circuit simulation (Caphe).

Device exploration

For the creation of device exploration masks, IPKISS provides features for creating component parameter sweeps and stacking on chip.

## Library management

The customer can create his/her own library of components using the functionalities and tools described above. IPKISS allows to keep a unified description of building blocks with layout, compact model and device simulation recipes. The components can then be used from within IPKISS (python scripts) as well as L-Edit.