Bruce L. Booth

Low loss channel waveguides in polymers

The primary routes for creating polymeric channel waveguides are reviewed. Processes, materials, waveguide performance, and applications recently reported in the literature are covered. Emphasis is on an internal diffusion approach under development at Du Pont which has not been widely reported. The intent is to provide a perspective on the flexibility and versatility for fabricating polymer channel waveguides for practical integrated optic applications. >

Polyguide polymeric technology for optical interconnect circuits and components

The expanding information revolution has been made possible by the development of optical communication technology. To meet the escalating demand for information transmitted and processed at high data rates and the need to circumvent the growing electronic circuit bottlenecks, mass deployment of not only optical fiber networks but manufacturable optical interconnect circuits, components and connectors for interfacing fibers and electronics that meet economic and performance constraints are absolutely necessary. Polymeric waveguide optical interconnection are considered increasingly important to meet these market needs. DuPonts polyguide polymeric integrated optic channel waveguide system is thought by many to have considerable potential for a broad range of passive optical interconnect applications. In this paper the recent advances, status, and unique attributes of the technology are reviewed. Product and technology developments currently in progress including parallel optical ink organization and polymer optical interconnect technology developments funded by DARPA are used as examples to describe polyguide breadth and potential for manufacture and deployment of optical interconnection products for single and multimode telecom and datacom waveguide applications.

Optical waveguide circuit board with a surface-mounted optical receiver array

A photonic circuit board is fabricated for potential application to interchip and interboard parallel optical links. The board comprises photolithographically patterned polymer optical waveguides on a conventional glass-epoxy electrical circuit board and a surface-mounted integrated circuit (IC) package that optically and electrically couples to an optoelectronic IC. The waveguide circuits include eight-channel arrays of straights, cross-throughs, curves, self-aligning interconnects to multifiber ribbon, and out-of-plane turning mirrors. A coherent, fused bundle of optical fibers couples light between 45-deg waveguide mirrors and a GaAs receiver array in the IC package. The fiber bundle is easily aligned to the mirrors and the receivers and is amenable to surface mounting and hermetic sealing. The waveguide-receiver-array board achieved error-free data rates up to 1.25 Gbits/s per channel, and modal noise was shown to be negligible.

Optical interconnects: the Parallel Optical Link Organization (POLO) approach

The Parallel Optical Link Organization (POLO) is an industry consortium of Hewlett-Packard, Du Pont, AMP, University of Southern California, and SDL, supported by ARPA and will operate between August 1994 and August 1997. The POLO Consortium was formed to leverage the individual strengths of its members to develop low-cost, high-performance optical interconnect modules for applications in workstation clusters, high-speed switching systems, and multimedia. The goal of the program is to demonstrate the manufacturability of affordable optoelectronic transceiver modules and to provide application platforms that show a clear advantage over copper-wire interconnections. The technical objective of the program is to provide a 10 - 20 Gb/s parallel channel optical interconnect module with a projected manufacturing cost of about

Recent developments in polymer waveguide technology and applications for data link and optical interconnect systems

10 per channel. In addition, the POLO Consortium provides a complete solution to the end user, including a programmable host interface module and software interface. The POLO Consortium has formed a User Group consisting of seven world-leading computer, telecommunication, and optoelectronic subsystem manufacturers. Regular meetings with the User Group are planned and at the first meeting, a full set of POLO Module specifications have been discussed and generated. The POLO Consortium will provide the User Group members with hardware for evaluation and feedback.

High-density interconnects for two-dimensional VCSEL arrays suitable for mass scale production

Low-cost robust optical interconnections interfacing solid state components, functional optical circuitry and optical fibers are increasingly needed to facilitate deployment of high capacity optical communication systems. Polymeric waveguide based optical circuits are being increasingly considered for these interconnect applications. Many applications are in development or early commercial stages. Some of these are highlighted in the presentation to provide a review of promising polymer based applications and technologies. In particular, PolyguideTM polymeric integrated optic waveguide technology, currently being applied in the ARPA funded POLO and POINT programs is covered in more detail. These programs are focused on high speed optical data links and optical circuit board technology respectively.

Gigabit parallel fiber optic link based on edge emitting lasers

Polymer waveguides provide cost effective interconnect solutions for high-volume applications required by the rapid growth in VCSEL array sizes and product demand. Multimode polymer waveguides 34-channels wide have been stacked in arrays 12-layers high with center-to-center waveguide spacing of 125 +/- 2 microns between layers and 90 +/- 2 microns within a layer. No measurable crosstalk between channels has been observed even when separation between multimode waveguides was reduced to a 4-micron gap. Flexible polymers provide an out-of-plane bend radius of less than 5 mm that simplifies VCSEL packaging requirements and volume. Transitioning the waveguide pitch within and between the polymer layers from 125 to 250 microns enables interface of high-density VCSEL arrays to standard fiber ribbons. Passive fiber pigtailing to 62.5/125 fibers was achieved with < 0.5 dB loss. Pigtailing can be avoided entirely by direct connectorization of the polymer waveguide arrays with industry standard MT connectors. Optical CrossLinks Guidelink polymer waveguide devices are made form sheets several hundred feet long. Waveguides are formed using contact photolithography that requires no costly spin- coating, wet chemistry, embossing, modeling or etching techniques required by other planar waveguide fabrication processes. All required processes are suitable for automation with high-yield while at the same time drastically reducing the infrastructure required to produce devices. Currently, the equivalent of 100 six-inch wafers of planar waveguides can be produced in less than 2 days without automated machinery.

Polyguide technology for passive optical interconnects

We present a 10 channel parallel fiber optic link consisting of a transmitter based on an edge emitting laser diode array operating at 980 nm and a complementary receiver based on an InGaAs pin photodetector array. We demonstrate link performance up to data rates of 1 Gbit/s with measurement time limited bit errors rates lower than 10/sup -11/ over 100 m of multi-mode fiber ribbon cable.

Excimer laser micromachining for passive fiber coupling to polymeric waveguide devices

DuPont has developed an optical interconnect technology consisting of polymer materials and fabrication and assembly processes. This technology, referred to as Polyguide, provides the user with the capability to mass produce channel optical waveguides that perform splitting, point to point interconnection, wavelength discrimination and other optical functions. These materials and processes make packaging practical. This has been demonstrated with optical printed wiring boards, connectorized multilayer ceramic modules and discrete pigtailed components. Critical interfacing requirements have also been met. These include the passively aligned attachment of single mode optical fiber arrays and the fabrication of low loss mirrors for coupling to laser diodes, LEDs, and photodectors. As part of the ARPA funded POLO project DuPont is advancing the fabrication and assembly processes to allow low cost deployment of optical interconnects. A description of current Polyguide technology and performance specifications will be presented. Demonstrations of packaging will be reviewed. This polymer system addresses most of the tasks required for the practical utilization of optical waveguides. Polyguide technology can enable optical connectivity and transmission in many new products.

Spatial frequency carrier and process of preparing same

The precise control and high-resolution ablation capability inherent in excimer laser machining make it ideally suited for creating slots for passive alignment of optical fibers to planar channel waveguides as well as for direct waveguide-to-waveguide coupling. This paper describes KrF excimer laser generation of passive alignment coupling slots and the results achieved using this technique with Polyguid polymeric integrated optic system single and multimode waveguide coupling.