A multi-channel free-space micro-optical module for dense MCM-level optical interconnections has been designed and fabricated. Extensive modeling proves that the module is scalable with a potential for multi-Tb/s.cm2 aggregate bit rate capacity while alignment and fabrication tolerances are compatible with present-day mass replication techniques. The micro-optical module is an assembly of refractive lenslet-arrays and a high-quality micro-prism. Both components are prototyped using deep lithography with protons and are monolithically integrated using vacuum casting replication technique. The resulting 16-channel high optical-grade plastic module shows optical transfer efficiencies of 46% and inter-channel cross talks as low as -22 dB, sufficient to establish workable multi-channel MCM-level interconnections. This micro-optical module was used in a feasibility demonstrator to establish intra-chip optical interconnections on a 0.6μm CMOS opto-electronic field programmable gate array. This opto-electronic chip combines fully functional digital logic, driver and receiver circuitry and flip-chipped VCSEL and detector arrays. With this test-vehicle multichannel on-chip data-communication has been achieved for the first time to our knowledge. The bit rate per channel was limited to 10Mb/s because of the limited speed of the chip tester.
We fabricated and replicated in semiconductor compatible plastics a multichannel free-space optical interconnection module designed to establish intra-chip interconnections on an Opto-Electronic Field Programmable Gate Array (OE-FPGA). The micro-optical component is an assembly of a refractive lenslet-array and a high-quality microprism. Both components were prototyped using deep lithography with protons and were monolithically integrated using a vacuum casting replication technique. The resulting 16-channel module shows optical transfer efficiencies of 50% and interchannel crosstalks as low as -22 dB. These characteristics are sufficient to establish multichannel intra-chip interconnects with OE- FPGAs. The OE-FPGA we used was designed within a European co- founded MEL-ARI consortium, working towards a manufacturable solution for optical interconnects between CMOS ICs. The optoelectronic chip combines fully functional FPGA digital logic with the drivers, receivers and flip-chipped optoelectronic components. It features 2 optical inputs and 2 optical outputs per FPGA cell, amounting to 256 photonic I/O links based on multimode 980-nm VCSELs and InGaAs detectors.
We report on the design, the fabrication, the characterization and the demonstration of scalable multi-channel free-space interconnection components with the potential for Tb/s.cm2 aggregate bit rate capacity over inter-chip interconnection distances. The demonstrator components are fabricated in a high quality optical plastic, PMMA, using an ion-based rapid prototyping technology that we call deep proton lithography. With the presently achieved Gigabit/s data rates for each of the individual 16 channels with a BER smaller than 10(superscript -13 and with inter-channel cross-talk lower than -22dB the module aims at optically interconnecting 2-D opto-electronic VCSEL and receiver arrays, flip-chip mounted on CMOS circuitry. Furthermore, using ray-tracing software and radiometric simulation tools, we perform a sensitivity analysis for misalignment and fabrication errors on these plastic micro-optical modules and we study industrial fabrication and material issues related to the mass-replication of these components through injection-molding techniques. Finally we provide evidence that these components can be mass-fabricated in dedicated, highly-advanced optical plastics at low cost and with the required precision.
We analyze the potentialities of microlens-based free-space optical pathway blocks for on-chip interconnects. To assess the promises of these modules, researchers typically make use of simple analytic Gaussian beam propagation (GBP). Although this approach leads to a first order layout of a microlens system it does not include aberrations. Aberrations however and -- spherical aberrations in particular -- become important when lenses with a small focal number are implemented. This is especially true when surface emitting lasers with a relative high beam divergence such as e.g. VCSELs are used. In this paper we evaluate how these aberrations affect the performances of such optical interconnection systems and we verify the validity of the GBP method. We enter various GBP layouts in the photonics design software SOLSTIS, which traces real rays or propagates spatially coherent optical beams through the system. We model and compare the performances of different microlens-relay system configurations and we focus on optical efficiency and scalability issues of these micro-optical interconnection components. To conclude we relate optical pathway lengths to minimum microlens diameters and to maximum achievable channel densities.
In this paper we present our latest results on the fabrication and characterization of plastic microlenslet arrays using Deep Lithography with Protons (DLP) and highlight their geometrical dimensions, their surface profile and their uniformity. We also present quantitative information on their optical characteristics such as focal length and spherical aberration as measured with a Mach-Zehnder interferometer. Furthermore we demonstrate the flexibility of the DLP technology to fabricate arrays of microlenses that feature different pitches and different sags. Although the DLP technology is a valuable tool to rapidly prototype refractive micro-optical components, the approach is unpractical for mass-fabrication. We therefore introduce a replication technique, called vacuum casting, which is very appropriate when only a few tens of copies have to be made, and we bring forward the first quantitative characteristics of these microlens replicas.
We present different configurations for a compact free-space
optical interconnection module by combining two radial gradientrefractive-
index lenses and/or two arrays of refractive microlenses.
Based on our findings with ray tracing and radiometric analysis, we discuss
how we have selected the proper optical system configurations and
how we have chosen the different design parameters to optimally accommodate
different types of optoelectronic emitters such as LEDs, microcavity
LEDs, and vertical-cavity surface-emitting lasers. We focused
on maximizing optical coupling efficiencies and misalignment tolerances
while minimizing interchannel crosstalk.
We report on the design, the fabrication, the characterization and the demonstration of scalable multi-channel free-space interconnection components with the potential for Tb/s.cm2 aggregate bit rate capacity over inter-chip interconnection distances. The demonstrator components are fabricated in a high quality optical plastic, PMMA, using an ion-based rapid prototyping technology that we call deep proton lithography. With the presently achieved Gigabit/s data rates for each of the individual 16 channels with a BER smaller than 10-13 and with inter-channel cross-talk lower than -22dB the module aims at optically interconnecting 2-D opto-electronic VCSEL and receiver arrays, flip-chip mounted on CMOS circuitry. Furthermore, using ray-tracing software and radiometric simulation tools, we perform a sensitivity analysis for misalignment and fabrication errors on these plastic micro-optical modules and we study industrial fabrication and material issues related to the mass- replication of these components through injection-molding techniques. Finally we provide evidence that these components can be mass-fabricated in dedicated, highly-advanced optical plastics at low cost and with the required precision.
In this paper we present different configurations for a compact free-space optical interconnection (FSOI) module by combining two radial gradient refractive index lenses (GRIN) and/or two arrays of refractive microlenses. Based on our finding with ray-tracing and radiometric analysis we discuss how we have selected the proper optical system configurations and how we have chosen the different design parameters to optimally accommodate different types of opto- electronic emitters such as LEDs, micro-cavity LEDs and VCSELs. We hereby focused on maximizing optical coupling efficiencies and misalignment tolerances while minimizing inter-channel cross-talk. Furthermore we discuss the experimental optical characteristics of two such prototype modules that we completed together with the first experimental results of their use in parallel data communication demonstrator systems.
We report on the design, the fabrication, the characterization and the demonstration of a scalable multi- channel free-space interconnection components with the potential for Tb/x.cm2 aggregate bit rate capacity over inter-chip interconnection distances. The demonstrator components are fabricated in a high quality optical plastic, PMMA, using an ion-based rapid prototyping technology that we call deep proton lithography. With the presently achieved Gigabit/s data rates for each of the individual 16 channels with a BER smaller than 10-13 and with inter-channel cross-talk lower than -22dB the module aims at optically interconnecting 2-D opto-electronic VCSEL and receiver arrays, flip-chip mounted on CMOS circuitry. Furthermore, using ray-tracing software and radiometric simulation tools, we perform a sensitivity analysis fo misalignment and fabrication errors on these plastic micro- optical modules and we study industrial fabrication and material issues related to the mass-replication of these components through injection-molding techniques. Finally we provide evidence that these components can be mass- fabricated in dedicated, highly-advanced optical plastics at low cost and with the required precision.
We design and realize a scalable multi-channel free-space interconnection prototype with the potential for Tb/s.cm2 aggregate bit rate capacity over inter- and intra-MCM interconnection distances. The component is prototyped in a high quality optical plastic, PMMA, using deep lithography with protons. At present data communication is achieved at 622 Mb/s per channel with a BER smaller than 10-13 for the 16 channels with inter-channel cross-talks as low as -22dB. We perform a sensitivity analysis for misalignments and study the impact of fabrication errors on the performance of the interconnection module in case injection moulding would be the preferred mass-fabrication technique. We provide evidence that these modules can be mass-fabricated with the required precision in optical plastics suited for heterogeneous integration with semiconductor materials.
We present and demonstrate a novel proof-of-principle system with parallel optical input/output to perform mathematical morphological operations on discrete gray level images. Experimental results of erosion and dilation of 8 by 8 images are presented, as well as threshold decomposition of a 6-gray level image into series of binary slices.
The significant progress which has been made in the development of differential pairs and arrays of differential pairs of light-emitting thyristors has made the construction of optical computing systems with high speed interconnections a realistic possibility. In this paper we review our work on the practical implementation of these optoelectronic transceiver devices in systems and demonstrate most of the basic functionalities necessary to build a primitive digital parallel optical processor. We demonstrate the transcription of digital optical data between cascaded single elements and between 8 X 8 arrays of completely-depleted optical thyristor differential pairs. We also show results of digital optical logic NAND, NOR, AND, OR, NOT operations, logic plane to logic plane imaging with a diffractive fan-out and parallel digital data input with a computer controlled liquid crystal micro-display. As an example of a sub-system module which has reasonable complexity we focus on a demonstrator platform which combines optical thyristor logic planes, polarization- selective diffractive optical elements, liquid crystal variable retarders and large diameter gradient index lenses, and successfully demonstrate dynamically reconfigurable nearest neighbor interconnects. We conclude by discussing the future system performances in the light of system scalability.
We simulate and compare optical transmission efficiencies, throughputs and interconnection lengths of free-space and POF-based guided-wave multi-chip-module optical interconnection systems for different types of microcavity emitters.
We simulate and compare optical transmission efficiencies, throughputs and interconnection lengths of free-space and POF-based guided-wave optical interconnection systems for different types of microcavity emitters.
The technology of deep proton lithography in PMMA (poly methyl methacrylate) is a fabrication method for monolithic integrated refractive micro-optical elements and micro-mechanical holder structures, which allows structural depths in the order of several hundred microns[l.21. Different optical functions can he fabricated in one block and form monolithic integrated optical systems. In addition mechanical support structures and alignment features can he integrated with these optical systems. This paper will focus mainly on the technological requirements of the irradiation, development and diffusion setups. which are necessary to achieve predictable and reproducible results with deep proton lithography.
We demonstrate a 2.5 Gb/s optical intra-MCM data link with a four-channel micro-optical bridge. This bridge was fabricated by deep proton lithography and monolithically integrates cylindrical lenses and micro-mirrors.
The significant progress which as been made in the development of differential pairs and arrays of differential pairs of light-emitting thyristors has made the construction of optical computing systems with high speed interconnections a realistic possibility. In this paper we review our work on the practical implementation of these optoelectronic transceiver devices in systems and demonstrate most of the basic functionalities necessary to build a primitive digital parallel optical processor. We demonstrate the transcription of digital optical data between cascaded single elements and between 8 by 8 arrays of completely- depleted optical thyristor differential pairs. We also show results of digital optical logic NAND, NOR, AND, OR, NOT operations, logic plane to logic plane imaging with a diffractive fan-out and parallel digital data input with a computer controlled liquid crystal micro- display. As an example of a sub-system module which has reasonable complexity we focus on a demonstrator platform which combines optical thyristor logic planes, polarization- selective diffractive optical elements, liquid crystal variable retarders and large diameter gradient index lenses, and successfully demonstrate dynamically reconfigurable nearest neighbor interconnects. We conclude by discussing the future system performances in the light of system scalability.
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