Introduction

A tool for fast and accuratemodelling and design of large and

complete optical circuits

Layout of a 4x4 Resonant Router

ASPIC is a software for fast and accurate analysis,modelling and design of integrated and hybrid opticalcircuits without restrictions in dimensions andcomplexity. Its model-based approach does not needdescriptions at physical level, permitting to concentrateon the circuit functionality

ASPIC places in the context of large optical circuitssuitable for emerging scenarios such as opticalinterconnects, optical networks and widebandconnections

ASPIC is complementary to classical electromagneticsimulators and is many orders of magnitude faster andless memory consuming

ASPIC allows to analyse complete optical circuits,calculates the spectral behavior, synthesize devices,realize virtual experiments, carry out ‘what if’ and‘worst case’ analysis, compare measurements andsimulations for parameter extraction and estimate theyield, study the impact of technological tolerances andmuch more...

Description

ASPIC owns a powerful CAD board that permits toeasily build-up every circuit starting from the buildingblocks available in its library, without any restrictionin dimensions and complexity

The simulation of the circuit is carried out in thespectral domain and it is many orders of magnitudefaster than every electromagnetic simulator. Thespectral behavior of the circuit is returned in terms ofamplitude, phase, group delay, dispersion and stateof polarization from input and output ports arbitrarilychosen

Many sources can be defined at the same time andlocated virtually everywhere, each one with adesired spectral shape, and every point of the circuitis an accessible output port after just only onesimulation. The extension to time domain is plannedin a short future

Component library

Selected componentparameters

Circuit Layout

ASPIC window layout

A powerful and user-friendlygraphical interface

CharacteristicsBuild in a simple way an optical circuit, integrated orhybrid, of arbitrary complexity without specifyingphysical details such as waveguide dimensions andmaterial characteristics

Make use of analytical, numerical, empirical modelsand also experimental data to describe elements orcomplex devices

Define the abstraction level of componentsdescription according to the desired phase of theproject development and the level of expertise of theuser

Perform accurate, fast and reliable analysis ofpassive component. The high simulation efficiencyallows to carry out synthesis, optimizations,statistical analysis on tolerances and other studiesusually impossible to do with electromagnetictechniques

Export data and interact directly and bidirectionallywith tools at higher (system simulators) or lower(electromagnetic simulators and mask layoutdesigners) levels.

“What if” studies

Aging effects

Worst case analysis

Optimization

Statistical design

Virtual Experiments

Tolerances impact

Design Verification

Proof of concept

ASPIC potentialities

Tolerances impact analysis

LibraryA Library containing a multitude of elementarybuilding blocks is already available

ASPIC Library is based on models. Dependingon the complexity of the implemented models,ASPIC can be used for several purposes, fromthe “proof of concept” to quasi-electromagneticaccurate analysis. Every building block can bedescribed by few simple parameters or tailoredfor a very accurate and personalized description

Elementary building blocks as straight and bentwaveguides, directional couplers, MMI, etc.permit the realization of an unlimited number ofcircuits. Also structured building blocks asMach-Zehnder, ring resonators and Bragggratings are available

Users can create their own components andexpand the Library with custom devices andtechnology oriented parameters

The measured experimental behaviour of anycomponent can be loaded as well and usedinside a circuit

Examples of ASPIC elementary building blocks

Fields of applicationEducation: ASPIC realizes the best interactiveenvironment to explain and teach how an opticalcircuit works, which are the limits and thecapabilities, the sources of impairments and theirdetrimental effects and the impact on the pulseshape. Extremely easy to use, ASPIC permits toincrease the learning efficiency through an attractiveprocess

Research: ASPIC capability of abstraction fromthe physical layer allows to work on the ‘concept’and ‘idea’ level, increasing at maximum theefficiency of the ‘proof of concept’ or ‘feasibility’phases. By concentrating on the circuit and itstransfer function, new and original circuit solutionscan be tested and proved in a short time.Nevertheless, by using more sophisticated models,extremely realistic simulations are possible, withaccuracy similar to those obtained throughelectromagnetic simulators

Industry: ASPIC is a potential candidate for everyR&D unit of industries operating with optical circuits.It is of great help for avoiding the classical ‘cut andtry’ procedure typical of the development of everycommercial device. ASPIC can speed up thepathway that bring from the idea to the prototypeand to the final product reducing the time to market

A real filter forDWDM on CWDM

systems

An idealMach-Zehnder

From the simple …… ….to complete design

Circuit approach advantages are manifold. It is muchfaster and less memory consuming, it is more suitedfor the simulation of large circuits, permits toconcentrate on a higher level, abstracting from thetechnology and permitting to retrieve preciousinformation for the design of the circuit. An evenmore important aspect is the possibility to access tomore sophisticated calculations such asoptimization, sensitivity analysis, yieldestimation….etc.

Realize virtual experiments,evaluate aging effects,

compare measured and simulated results.....and much more!

Measured dataSimulation result

Comparison of a measured and simulated SiON waveguide spectral attenuation

Examples

Polarization conversion in asingle ring filter

TE

TM

How it worksThere are two main approaches in the investigationof devices and circuits, one physically based andone based on models. The first one tries to simulatethe real physical behavior by solving the equationsat the basis of the physical phenomena, such aspropagation of electromagnetic fields, waves, chargedisplacements, etc. ASPIC uses the secondapproach, modeling the phenomena staying behindthe physical mechanisms through equations that“behave-like” the real word.

ASPIC models each component with a scatteringmatrix. Matrices are assembled in a single largesparse matrix according to the topology of the circuitand then inverted to find the complex optical field ineach node of the circuit. These ports are the onlyobservable points of the circuits, where forward andbackward waves are defined.Instabilities and ill-conditioning are eliminated with apowerful scheme of variables reduction. Theknowledge on both the waveguiding structure andthe used materials are not necessary.

The two approaches are somewhat complementaryand permit to concentrate on different levels. Theemployment of an approach on the wrong level isinefficient or even impossible.

Model based approachfor high speed computation

and large circuit management

Acc

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Speed

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Electromagneticsimulators

Circuitsimulators

Positioning of Physically and Model based approaches

From the idea …… ….to the final design

Automatic GDSII generation of the circuit layout

Tools ASPIC comprises a number of useful tools for the postprocessing of simulated data. GDS II generator, filtersynthesis designer, yield estimators and others toolscan help the analysis without exporting and importingdata in other software

Whatever your field is, ASPIC will beyour precious, invaluable and powerfultool for development of optical devicesand circuits, exploiting measured andprocess data always in the spirit of‘Design for high yield and reliability’