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. >

Low loss channel waveguides in polymers

Work on deposited glass waveguides on silicon to form waveguides and filters is reviewed. The choice of these particular waveguides makes sense only as part of a consistent approach to optoelectronic packaging. Hybrid optical packaging on silicon (HOPS) is described and briefly compared with other techniques. For these packages, two waveguides were developed: a tight mode waveguide with a silicon nitride rib core for matching a semiconductor laser and a loose mode waveguide with a phosphosilicate glass core for matching an optical fiber. >

Glass waveguides on silicon for hybrid optical packaging

An apparatus for forming an optical element on the surface of a substrate by ejecting a curable light guide forming liquid from a nozzle onto the substrate and curing the curable light guide forming liquid A waveguide may be formed by moving the nozzle in a linear pattern over the surface of the substrate during ejection of the liquid from the nozzle Curing the liquid may include exposing the liquid to ultraviolet radiation, and the radiation may be applied to only a small portion of the liquid A multilayered waveguide may be formed by ejecting a further light guide forming liquid onto the first and curing it A core and cladding may be formed simultaneously by ejecting core forming liquid from an inner tube and cladding forming liquid from an annulus about the inner tube The waveguide may be formed in a groove, and a splitter may be formed by branching a second waveguide from a first, or by laying out two parallel waveguides and connecting them Apparatus for forming a light guide on a substrate includes an xy movable support for the substrate, and a container having a nozzle, the nozzle being movable in relation to the substrate, and a dispenser to regulate dispensing of liquid from the container Liquid curing radiation may be provided through a source of UV light The nozzle may be formed of a first central tube and a second outer tube disposed about the first central tube to form an annulus between them A microlens may be formed by holding the nozzle stationary during dispensing

Method and apparatus for making optical components by direct dispensing of curable liquid

Optoelectronic interconnections can provide a practical solution for the ever increasing communication bottleneck problems when combining a multitude of information processing units to perform a function. As research activities progress in the field of serial or parallel board-to-board and module-to-module interconnections, some of the research focus has shifted to smaller physical dimensions, like intra-module interconnections, which combines optoelectronic interconnections, multichip module packaging, and microelectromechanical system (MEMS) technologies at the module level. The present invention provides integrated optical input/output (I/O) couplers on multichip modules (MCMs) using micro-machined silicon mirrors that are used with optoelectronic multichip modules (OE-MCMs). The present invention used microstructures that integrate optical waveguide networks, multilayer electrical transmission line networks, micro-machined silicon mirrors, and C4-bonded photonic devices into a single structure. Using both sides of the silicon wafers, multiple metal layers and optical waveguide layers are fabricated for all types of metal or optical waveguide materials. The input/output coupling arrangement utilizes a combination of micro-machined silicon mirrors and through-holes across OE-MCM, integrated together into a single package. Fabrication strategies and possible applications of the invention are disclosed herein.

Method and apparatus for providing a seamless electrical/optical multi-layer micro-opto-electro-mechanical system assembly

An experiment in which a high-power mode-locked femtosecond semiconductor laser system was used as a source of extremely low jitter intense optical pulses in the distribution of a clock to 1024 ports via optical fibers is described. The total accumulated dynamic clock jitter between any two ports, which contains both correlated and uncorrelated sources, was measured to be less than 12 ps. This laser system produced a train of 460-fs optical pulses with over 70 W of peak power at 302 MHz. These results represent the largest fanout with the minimum timing jitter for an optically distributed clocking network. >

Optical clock distribution using a mode-locked semiconductor laser diode system

The use of optics as an alternative method for achieving very high speed (10 Gb/s > bit rate > 500 Mb/s) electrical interconnects is the subject of this paper. Optical interconnect media considered include plastic channel waveguides, glass waveguides, fibers, and free-space interconnects. Typical interconnection distances considered are inches or less. The problems of cou-pling and interconnecting and their overall effect on system power budgets are also discussed. As a means of quantifying the results, link budgets for a 565 Mb/s, a 2.3 Gb/s, and a 4.6 Gb/s interconnect scenario are made. Multipoint as well as single-point-to-single-point situations are considered.

Digital High Speed Interconnects: A Study Of The Optical Alternative

We report a simple technique for patterning channelized optical waveguides on standard electronic printed circuit card material. The technique exploits the abundance of transparent, radiant-curing polymer adhesives in the fiber optics and the dental industries. The process is compatible with standard printed circuit card fabrication processes; hence its applicability to optical interconnection scenarios. We report typical guide losses in the 0.4–0.6-dB/cm range. Measurements were made using an automated noninvasive, nondestructive technique, also briefly described here. Simple structures, such as splitters, bus lines, and 90° bends were fabricated and are described. Optical coupling to the waveguides from packaged devices is also discussed.

Radiant cured polymer optical waveguides on printed circuit boards for photonic interconnection use.

A focused argon‐ion laser beam (λ=350 nm) is used to fabricate optical channel waveguides on oxidized silicon wafers using a commerically available spin‐on polymer. The polymerization process is photon induced, thus allowing the reaction to occur in a room‐temperature ambient. This allows the fabrication of waveguides on a variety of substrates including those with low melting points. The losses in these waveguides are typically less then 1 dB/cm, making them applicable to a variety of optical interconnect problems. In particular, we demonstrate their use in the fabrication of an optical power tap.

Laser direct writing of channel waveguides using spin‐on polymers

The device requirements and system design issues for board-level optical links differ from their counterparts in optical links used for longer distance communications. We have fabricated a research prototype of a board-level optical link which is designed to operate in a high-speed digital equipment internal interconnect environment. The experimental transmitter and receiver packages are specifically designed for subminiaturized applications. We have explored the use of photolithographically patterned waveguides made of polymers as an alternative to the use of fiber at the board level. The major aspects of the device design are reviewed, but the emphasis of this paper is the systems-level design issues. We will discuss the design goals and the performance of the link. The results of this work demonstrate the feasibility of optics for signal distribution at the board level.

Board Level High Speed Photonic Interconnections: Recent System Developments

An investigation of potential physical design bottlenecks in future broadband telecommunication switches has led to the identification of several areas where optical interconnections may play a role in the practical realization of required system performance. In the model used the speed and interconnection densities as well as requirements for ease-of-access and efficient power utilization challenge conventional partitioning and packaging strategies. Potential areas where optical interconnections may relieve some of the physical design bottlenecks include fiber management at the customer interface to the switch routing and distribution of high-density interconnections within the fabric of the switch and backplane interconnections to increase system throughput.© (1991) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Davis H. Hartman

Papers

Digital High Speed Interconnects: A Study Of The Optical Alternative

Radiant cured polymer optical waveguides on printed circuit boards for photonic interconnection use.

Laser direct writing of channel waveguides using spin‐on polymers

Board Level High Speed Photonic Interconnections: Recent System Developments

Potential roles of optical interconnections within broadband switching modules