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On the basis of a realized 12times10 Gb/s card-to-card optical link demonstrator, the capabilities of a polymer-waveguide-based board-level optical interconnect technology are presented. The conception and realization of the modular building blocks required for this board-level optical interconnect technology are described in detail. In particular, we report on the fabrication and characterization of board-integrated optical low-loss polymer waveguides that are compatible with printed circuit board (PCB) manufacturing processes. We also explain our fully passive alignment technique, superseding time-consuming active positioning of components and connectors. To realize optical transceiver modules comprising vertical cavity surface emitting laser (VCSEL) arrays with laser drivers and photodetector arrays with transimpedance amplifiers (TIAs), a mass-production concept based on wafer-level processing has been elaborated and successfully implemented.

We report on the 3D integration and interconnect of top-emitting VCSEL and photodiode (PD) arrays on a CMOS substrate. This technology represents a radically new way to increase the I/O bandwidth of processors and enables a path beyond 10Tb/s I/Os by using a high level of integration of opto-electrical devices (OED) directly on the processor. The integration process developed includes an OED placement of better than [email protected], OED thinning down to [email protected], and an interconnect technology with copper vias into the planarization polymer. Although the process is fully compatible with the back-end-of-line of CMOS, the experiments performed were done on dummy CMOS wafers. The opto-electrical characterization performed revealed a minimal impact of the integration process on the OED performance, demonstrating the high potential of the concept.

There has recently been increased interest in carbon-based resistive random-access (RRAM) memory. Carbon-based RRAM has the potential to scale to atomic dimensions, resulting in ultra-high-density and low-power memory. Here we report reversible unipolar resistance switching in hydrogenated amorphous carbon. The devices used in this study are fabricated using e-beam lithography with built-in series resistors. A thorough analysis of the electrical transport and the resistance switching mechanism is presented.

We report on a card-to-card optical interconnect demonstrator with passively aligned butt-coupled optoelectronic modules onto waveguides embedded into the printed circuit board (PCB). After describing selected building blocks, we will present experimental results obtained with the demonstrator hardware consisting of a parallel 12-channel at 10 Gb/s (120 Gb/s) optical card-to-card link.

Optical waveguides embedded in a printed circuit board offer a substantial increase in the achievable bandwidth density compared with todays electrical interconnects. Specific challenges and solutions to integrate optical interconnects in a printed circuit board are addressed.

A successful implementation of optics into PCBs (printed circuit boards) requires a precise passive alignment of optical elements relative to the optical waveguides in the board. We tackled this challenge with a novel concept that allows the passive alignment onto a PCB of any optical or optoelectronic building block with a precision of a few micrometers. Markers, structured into a copper layer during manufacturing, are used as a position reference for the polymer waveguide fabrication and for the formation of mechanical alignment features. To form the latter, laser drilling, a standard process for via formation in PCBs, is used. We were able to demonstrate repeated insertions of adapter elements into these alignment slots with a standard deviation of 3 /spl mu/m for in-plane displacements. Afterwards, optical modules were mounted onto the adapters, using a standard MT interface provided by the adapter. We measured a standard deviation of the order of 5 /spl mu/m for the in-plane and out-of-plane misalignments of the module with respect to the optical waveguides. The passive alignment concept demonstrated enables accurate and simple plug-in of any kind of element, in particular of optical and opto-electronic elements, into a PCB. The concept is based on established PCB manufacturing processes, which is crucial for the development towards a low-cost optical interconnect technology.

This paper presents the Butt-coupled silicon optoelectronic modules for high-speed optical interconnects. The optoelectronic (OE) modules is populated by flip-chip bonding either with VCSELs or detectors placed in direct contact with the waveguides without additional optical elements. The light is guided through the Si module by integrated waveguides based on holes etched through the silicon, which are then oxidized and filled with a polymer. This integrated OE module concept requires only one alignment step in the board and is compatible with a multi-layer waveguide approach. Data transmission of up to 5 Gbps has been demonstrated.

Polymer waveguides embedded in a printed circuit board offer a substantial increase in the achievable bandwidth density compared with today's electrical interconnects. We present our results on the polymer waveguide technology and the building blocks that perform the optoelectronic conversion. Specific challenges in integrating optics in a printed circuit board are addressed. Data transfer measurements are presented.

Building blocks and experimental results of an optical card-backplane-card link with waveguides embedded into the boards and butt-coupled optoelectronic modules are presented. Important next steps for acceptance of the technology by system developers are listed.

We discuss some of the trade-offs that we are facing when choosing design parameters for future optical backplane interconnects. We present some of our current choices, along with experimental module- and system-level results.

We report on the material evaluation, design, fabrication, and characterization of low-loss multimode polymer waveguides that are compatible with standard PCB manufacturing processes for use in large-area high-density high speed optical backplane interconnects.

We present the development of a 4×4 matrix of optical switches based on silicon microfabricated switches and integrated waveguides. The device consists of two chips connected together by flip-chip bonding. The first chip has 16 latched silicon switches with micro-mirrors, while the second one contains the integrated waveguides and ensures the electrical connection of the 16 switches. The incorporation of integrated waveguides, patterned using a SU-8 mask and deep reactive ion etching, in our switch devices allows both the size and the packaging complexity to be reduced, and a technology for higher order matrices to be developed.

We present the design and characterization of a new 4 X 4 switch based on the previously developed 2 X 2 fiber switch. The switching principle uses plasma etched vertical mirrors that can be moved in and out of two pairs of optical fibers with the integrated electrostatic actuator. The 4 X 4 switch is built by connecting 16 individual 2 X 2 switches in a common package (100 X 50 X 35 mm). Instead of integrating the 16 switch elements on the same chip, we preferred assembling the switches by fusion splicing. The insertion loss is less than 1.8 dB for each state.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Briefly reports on advances in the fabrication technology of components for millimeter size ultrasonic piezoelectric motors. A very large height to width aspect ratio with good lateral patterning resolution is required for the active component in acoustic mode conversion. A new fabrication process using a thick epoxy-based material (SU-8) and the electroplating of nickel is demonstrated. The main advantages over past fabrication methods are better flexibility in the design, simplicity of the fabrication process and the combination of metallic materials (Ni) with polymeric materials (SU-8). The mechanical properties of SU-8 have been measured using free cantilever beam structures.

This paper will focus on the fabrication and characterization of two types of piezoelectric motors based on the elastic force motor principle. The initial motivation for this work was the development of a motor for wristwatch applications, combining high torque (1 /spl mu/m) with low power consumption (10 /spl mu/W) and small dimensions. Previously reported motors were based on a hybrid assembly of a copper-beryllium rotor, obtained by laser cutting, and a stator consisting of a circular membrane, clamped along its border. The membrane was anisotropically etched in silicon and covered with either ZnO or PZT. We report on an improved and further miniaturized version with fully microfabricated rotors and a new stator design.