A glass optical waveguide process has been developed for fabrication of electro-optical circuit boards (EOCB). Very thin glass panels with planar integrated single-mode waveguides can be embedded as a core layer in printed circuit boards for high-speed board-level chip-to-chip and board-to-board optical interconnects over an optical backplane. Such singlemode EOCBs will be needed in upcoming high performance computers and data storage network environments in case single-mode operating silicon photonic ICs generate high-bandwidth signals . The paper will describe some project results of the ongoing PhoxTroT project, in which a development of glass based single-mode on-board and board-to-board interconnection platform is successfully in progress. The optical design comprises a 500 μm thin glass panel (Schott D263Teco) with purely optical layers for single-mode glass waveguides. The board size is accommodated to the mask size limitations of the fabrication (200 mm wafer level process, being later transferred also to larger panel size). Our concept consists of directly assembling of silicon photonic ICs on cut-out areas in glass-based optical waveguide panels. A part of the electrical wiring is patterned by thin film technology directly on the glass wafer surface. A coupling element will be assembled on bottom side of the glass-based waveguide panel for 3D coupling between board-level glass waveguides and chip-level silicon waveguides. The laminate has a defined window for direct glass access for assembling of the photonic integrated circuit chip and optical coupling element. The paper describes the design, fabrication and characterization of glass-based electro-optical circuit board with format of (228 x 305) mm2.
This paper summarises our work on modulators for integration, either as a front end approach, or a co-location of custom electronic drivers, approaches that have yielded data rates up to 50Gb/s from a range of device variants. As well as more conventional depletion based devices, we also report photonic crystal cavity based modulators for very low power consumption, as well as other device variants aimed at improving device performance metrics.
Silicon photonics have generated an increasing interest in the recent year, mainly for optical
telecommunications or for optical interconnects in microelectronic circuits. The rationale of silicon photonics
is the reduction of the cost of photonic systems through the integration of photonic components and an IC on a common chip, or in the longer term, the enhancement of IC performance with the introduction of optics inside
a high performance chip.
In order to build a Opto-Electronic Integrated circuit (OEIC), a large European project HELIOS has been
launched two years ago. The objective is to combine a photonic layer with a CMOS circuit by different
innovative means, using microelectronics fabrication processes. High performance generic building blocks
that can be used for a broad range of applications are developed such as WDM sources by III-V/Si
heterogeneous integration, fast Si modulators and Ge or InGaAs detectors, Si passive circuits and specific
packaging. Different scenari for integrating photonic with an electronic chip and the recent advances on the
building blocks of the Helios project are presented.
A method of inverse design is applied to generate a new family of optical devices named scattering optical elemetns
(SOE). The two dimensional (2D) designs consist of a few layers of 0.4&mgr;m x 0.4&mgr;m square-shaped bars etched
in gallium arsenide. SOEs are defined as a class of computer-generated optical devices whose functionalities are
based on the multiple scattering by their individual constituents. For realization of the aforementioned devices,
two-dimensional photonic plates could be fabricated by only a single integrated circuit processing procedure
followed by micromanipulation assembling. A small library of compact SOE devices are presented: A focusing
device, a wavelength de-multiplexer, an optimized optical source, an optical MEMS switch and a cloaking device.
A method of inverse design is applied to generate a new family of optical devices. Three ultracompact devices are presented of only a few microns thick; a focusing device, a wavelength de-multiplexer and an optimized optical source. The designs consist of a few layers of 0.4μm × 0.4μm square-shaped bars etched in gallium arsenide. The proposed designs are examples of a scattering optical element, a name introduced to define a class of computer-generated optical devices whose functionalities are based on the multiple scattering by their individual constituents. For realization of the aforementioned devices, two-dimensional photonic plates could be fabricated by only a single integrated circuit processing procedure followed by micromanipulation assembling.
We use multiple scattering in conjunction with a genetic algorithm to reliably determine the optimized photonic-crystal-based structure able to perform a specific optical task. The genetic algorithm operates on a population of candidate structures to produce new candidates with better performance in an iterative process. The potential of this approach is illustrated by designing a spot size converter that has a very low F-number (F=0.47) and a conversion ratio of 11:1. Also, we have designed a coupler device that introduces the light from the optical fiber into a photonic-crystal-based wave guide with a coupling efficiency over 87% for a wavelength that can be tuned to 1.5 λ.