APSS Unique Features(Comparison with Conventional Simulators)

Circuit Simulator

APSS is the only Photonic CAD tool that can analyze complex integrated circuits. Regular methods, such as FDTD, cannot be used to analyze circuits due to its large size. Some circuits contain 90 or 180 degree bends that make them impossible to be used by standard simulators such as BPM. APSS has a specific simulator for photonic circuits. The concept has been well accepted in electronics circuit design, i.e., LSI performance is calculated by small sub circuits which build up LSI. The GUI (Graphic User Interface) of APSS is so powerful and easy to use so designers can easily create any complex circuits.

Application oriented rather than method orientedl

Unlike other photonic tools that has only one numerical method, such as BPM or FDTD, APSS does not focus on the method. It has all the numerical and analytical methods, and a proper one is selected for a specific design.
Take a simple step junction. If user wants to evaluate the transmission, APSS provides BPM. If user also interested in the reflection, APSS uses BPM+FDTD. All setting is embeded in the software, and user can define its own setting to investigate the device performance.
Another example could be S-bend, or a Elliptical bend. There are a number of different analytical and numerical methods available for this kind of devices. If the user wants to have a quick estimation of the transmission loss and return loss, 2D analytical method could be selected. That includes:
a) Effective index method to reduce the 3D problem into 2D,
b) Neural-Network to estimate the bending loss and phase delay,
c) Mode matching method for the transmission and reflection at junctions.
In case users require rigorous numerical calculation, 2D or 3D Cylindrical BPM will be used to trace the wave propagation step by step in a cylindrical coordinate system along the bend.

Complete solution with fully integrated hierarchical framework
APSS offers complete design solution from basic selecting materials to the final exporting mask files of a photonic integrated circuit (PIC). To simplify a design work, APSS is designed in a hierarchical framework consists of Material, Waveguide, Device, and Circuit modules according to the current processing technology procedure. This way, a big and complicate design problem can be decoupled into a number of smaller and simpler problems in order to be solved step by step, may by different people with different expertise by different specialized solvers.

By modulling the PICs, designers could focus on the separated issues at different stages. Similar to the processing technology, different stage may required different and combined expertise, such material science, processing technology, optical/electromagnetic/RF theories, as well as packaging technology.

Therefore, APSS provides an integrated platform for a group of designers can work together on a complex project and a specific module for individual designer to work on a specific problem. It provide a complete solution from basic material to final mask file for PIC designers.

Knowledge based with pre-defined libraries
To overcome the entrance barrier and shorten the learn curve for new users, all the possible known knowledge is built in those pre-defined libraries and user do not need to read all the details before they can start the design work. This also saves designers' time and effort in creating some of the popular material, waveguide, and devices such as
Silica or InP materials with different types of doppings
Multilayer Ridge, Channel, and Multistep waveguides
MMI, directional couplers, star couplers, junctions, tapers, and AWG

In addition to those pre-defined libraries, APSS provides a User-defined environment for advanced users to design those waveguides and devices which are not included in the library.

General Features
Beside the above general features, APSS has several important features which some of them are unique in Apollo software. Some of APSS features are:

Material Module
Silica based material with different dopings, such as GeO2, P2O5, and B2O3
Library for InGaAsP/InP material system

Waveguide Module
Library of common waveguides
Any types of modes: Higher order, bending, guided, and leaky
Complete modal characteristics
Far field and near field calculations
Overlap integral and waveguide coupling efficiency
Powerful mesh setting for fast and accurate analysis
Robust and powerful solvers
Devices with two cross sections

Device Module
Knowledge-based cell library for commonly used devices
Embedded algorithms, such as 2D & 3D BPM, FDTD, BPM+FDTD, CBPM, CMT...
Powerful mesh setting for fast and accurate analysis
Complete outputs: Field distributions, Insertion & Return losses, PDL, and PCL
Layout export in GDSII and DXF formats

Circuit Module
Smart connector setting among different devices, with an easy and flexible tool
Quick estimation of the insertion loss of the connector
Fast performance simulation of the integrated circuit
Complete outputs: Insertion/Return/Radiation losses, PDL, PCL