Gilles Jacquemod

FLAG: a flexible layout generator for analog MOS transistors

This paper describes a flexible MOS transistor layout generator which draws optimal layouts whatever the W and L dimensions. The drawing methodology is based on the use of small elementary parts, called bricks, which are placed side by side inside a user-specified boundary. The generated transistors may allow diffusion merging along whichever sides the user wishes and may have a global rectilinear shape. The internal structure of these cells may also be chosen by the designer so that it is well suited to his application. Transistors developed using this generator have been tested, and have been used to build a simple operational amplifier.

Simulation of electrothermal interactions in power integrated circuits

The authors present SETIPIC, a software package which couples electric and thermal simulations to forecast the electrothermal interactions in the first design steps of power integrated circuits. To give a consistent interface to the designer, SETIPIC is integrated in the EDGE CAD system PICMOST, the thermal simulator used by SETIPIC to obtain the thermal distribution on the layout surface in a transient or stationary mode, is also described. It takes into account the chip environment by the connection of different thermal networks, and uses an automatic mesh method to handle the layout configurations. An infrared experimental method is described to characterize the thermal distribution on a chip. This system was used to validate PICMOST. Some simulation results are given.<<ETX>>

Design automation of power integrated circuits in EDGE environment

Presents SETIPIC, a software package to forecast the electrothermal interactions in the first design steps of power integrated circuits. To give a well-consistent interface with graphic tools to the designer, SETIPIC works under the EDGE CAD system. The software aspect of this integration into EDGE is explained. PICMOST, the thermal simulator used by SETIPIC to obtain the thermal distribution on the layout surface in a transient or stationary mode is also described. In particular, the method to take into account the chip environment (package...) with an automatic mesh to handle aleatory layout configurations is explained. Finally, some thermal simulation results are given.<<ETX>>

Experimental validation of electrothermal simulations using SETIPIC for analogue integrated circuits

This paper presents the validation of SETIPIC-an electrothermal simulator for power integrated circuits. SETIPIC works by alternation of electrical simulations, using a SPICE-like simulator and thermal simulations using PICMOST-a three-dimensional thermal simulator we wrote to obtain the thermal distribution on the layout surface in a transient or stationary mode. Also, an infrared thermal measurement experimental set up was built to validate SETIPIC on an industrial IC and some thermal results are given.

SETIPIC: electrothermal simulator for power integrated circuits in EDGE environment

The authors present SETIPIC, a software to simulate the electrothermal interactions in the first design steps of power integrated circuits. To give a well-consistent interface to the designer, SETIPIC has been integrated in the EDGE CAD system. The software aspect of this integration is explained. SETIPIC works around SPICE3 (electric simulation) and PICMOST (thermal simulation). This thermal simulator which calculates the thermal distribution on the layout surface of a chip taken in its environment is also described. Finally, an infrared experimental set up is proposed to validate SETIPIC and some thermal and electrothermal simulation results are given.<<ETX>>

Behavioral modeling approach for optical communication network design

An optical communication networks can be divided in two levels: communication level, which defines the protocols, the control and the management of the networks and physical level formed by photonic and electronic components in order to transmit and receive the data between different nodes of the network. Traditionally, these two levels are considered separately in the optical communication network design process. This can lead to an erroneous or non-ideal networks implementation, due to the fact that the communication and physical levels are not independent. For example, in WDM communication network the maximum achievable data rate is limited not only by the networks protocol, but depends also on the implementation of the physical level: tuning delay of the optical multiplexers. Also the lack of the possibilities for co-verification of the communication and the physical levels together could lead to misinterpretations between the designers of the different levels and thus induce design faults. Since the prototyping is extremely expensive and time consuming, an integrated simulation of both communication and physical levels is necessary, at least in some extend. In this paper, a behavioral modeling approach that allows a co- simulation of the communication and the physical levels is presented. It is based on the use of a VHDL-AMS-like hardware description language, dedicated to electronic system modeling, but also suitable for modeling and simulation of non- electronic and mixed-domain systems. The behavioral models for photonic and electronic components, as well as the software are integrated in a unique simulator in order to co-simulate the communication (control) and the physical level (data path) of a WDM optical communication network.

Design and optimization of optical links based on VHDL-AMS modeling

This paper presents some examples of behavioral model hierarchies for optronic and photonic devices. The methods used to overcome the limitations of VHDL-AMS in modeling propagation phenomena are described. This work is part of an ongoing development of mixed-domain simulation tools for the design of optical links in a standard EDA framework.

Design and optimization of passive components for optical interconnects

In this paper, we present an optimization method for passive components such as straight waveguides, Y-couplers or microring resonators, in order to design optical interconnects and networks. We show that the optical interconnects used in telecommunication applications may also be used in photonic integrated circuits, especially in the case of parallel computing networks. In a first approach, we have taken an interest in modal constant propagation in order to describe signal transmission in integrated optical devices. In a second approach, FDTD simulations of Y-couplers have allowed us to optimize the shape of such devices, and to establish a behavioral model for a single-mode coupler. Moreover, a link between VHDL-AMS and the FDTD algorithm has been prosed in order to overcome problems encountered in the description of propagation phenomena at device and layout level.

Behavioral modeling of short-distance optical interconnects

This paper presents the modeling of an optical link based on VCSELs. A physics-based model of a VCSEL has been established and validated. The complete optical link has been modeled including free space propagation, Gaussian spatial repartition of light and photodetection. Concerning the photodetection, a low-noise, low-voltage, 2.5Gb/s CMOS photo receiver is being designed, so as to complete the optical link. Furthermore, system parameters such as BER or power consumption can be determined. This results in a fully self-consistent model of a short distance optical interconnection that ca be used to simulate board to board or chip to chip interconnections.

Improving resolution of solid state linear array x-ray detectors

Linear solid-state detectors are nowadays a widespread media in industrial and medical x-ray imaging. The resolution reached with this system has been largely improved in these past years, but is still too poor for some high resolution applications. We first have carried out an optimization of the detector characteristics through a behavioral simulation using a hardware description language. Furthermore, our work concerned the resolution enhancement for this kind of detectors via signal processing. Our approach takes into account the modeled point spread function (PSF) of the system. This modeled PSF is obtained with a new edge technique. The knowledge about the system response is used in a restoration scheme in order to improve the response of the detector to the high frequencies in the digital image. The restoration problem is an ill posed problem ad uses an inverse Wiener filtering. Another intrinsic limitation of solid-state detectors is the spatial sampling step. In order to overcome this problem, we also tested the feasibility of a finer sampling of the acquired image, buy interlacing several slightly shifted acquisitions of the same test object. The restoration applied to this finer sampled signal results in a resolution enhancement that is theoretically impossible to reach with a single detector acquisition. Some experimental results obtained on a variable bar-space pattern phantom are presented. This kind of phantom allows for a precise evaluation of the modulation transfer function on the acquired and processed images. The contribution of the image processing to the restoration enhancement can thus be quantified.