Optical interconnections applications

For data transfer applications the modulation speed of an emitter is a decisive parameter. Here the long lifetime of the excited state in PS becomes problematic. The fall time of the EL is usually in the ps regime, while somewhat shorter values are reported for the rise time. Only for devices based on OPS has a significantly shorter fall time (0.03 ps) been reported [WalO]. For small signal modulations of the EL from PS, frequencies in the order of 1 MHz are reported Ts4, Co5]. Such modulation frequencies are sufficient for display applications. For data transfer via optical interconnects, however, they are much too low. 

As the materials mature, it is expected that practical fabrication problems will be solved, and that eventually various grades of E-0 polymers will be available, like photoresist is today, for a variety of different applications and needs. For this reason, polymers represent a unique, potentially powerful addition to the library of materials comprising optoelectronic components, and polymer devices provide new and novel approaches to optical interconnection, electronic packaging, and integrated optics. 

Nanoparticles are rapidly gaining popularity in biomedical, optical and electronic areas. Zapping tumors with multi-walled carbon nanotubes, solar cells to light-attenuators and chip-to-chip optical interconnects in futuristic circuitry are some of the potential applications. Thus finding novel ways for the synthesis of these new age materials is of paramount interest where radiation chemistry is modesdy playing a role and the chapter on metal clusters and nanomaterials deals with these aspects. 

The most often discussed application of SPAs is optical interconnection. All applications of these arrays involve optical interconnection in one way or another, but the term optical interconnection most often refers to optical data channels between electronic processors and devices. This includes data transfer between machines, racks, boards, and chips. SPAs are being developed for optical interconnection at the board and chip level where the demand is very high for the dense packaging of the electronic and optical devices. Figure 2 illustrates two of several envisioned configurations for board-to-board and chip-to-chip optical interconnection. 

Much of this early effort dealt with modulator technology that is considered too slow (1-100 kilohertz) for high-speed applications such as optical interconnection and memory read/write. This includes modulators based on electrooptic effects in ferroelectric liquid crystals (ELCs) and in a ceramic containing lead, lanthanum, zinc, and titanium (PLZT). These electrooptic materials are bonded in some fashion to Si circuits to create hybrid SPAs. 

Level 5 (genius) pixels (thousands of transistors) have complexities, in general, above a thousand active devices, a level of complexity sufficient for implementing application-specific integrated circuits (ASICs) and microprocessors. But this functionality level has problems not faced by the lower levels. First, for free-space optical interconnection, optical I/Os should be arranged in a structured two-dimensional pattern in order to effectively use the two-dimensional nature of imaging optics. On the other hand, computer-aided design (CAD) tools for elec-... 

The printing fluids are often UV-curable, heat-sensitive, or conductive polymers for various applications. The resolution of the 3-D structure is limited by the size of droplet or nozzle, usually with diameters of 25-125 pm. The quality of the printing system determines the speed and precision of the spray and stage control. This technology is adopted in various applications of optical interconnect, electrical devices, microfluidic structures, and assembly. 

Large numerical aperture and short focal distance make the inkjet printing of microlenses very attractive for applications in optical interconnects and pixelated imagine sensors. This is a simple and a cheap alternative to the conventionally used photolithography (17). 

This article addresses key aspects of diffractive optics. Common analytical models are described and their main results summarized. Exact numerical methods are applied when precise characterization of the periodic component is required, whereas approximate models provide analytical results that are valuable for preliminary design and improved physical insight. Numerous examples of the applications of diffractive optical components are presented. These are optical interconnects, diffractive lenses, and subwavelength elements including antireflection surfaces, polarization devices, distributed-index components, and resonant filters. Finally, recording of gratings by laser interference is presented and an example fabrication process summarized. 

Liu, Y., Bristow, J., Marta, T., Bounnak, S., Johnson, K., Liu, Y., and Cole, H., Polymer waveguide applications in multichip modules (MCMs) and board level optical interconnects. Organic thin films for photonics applications, OSA Tech. Digest Sen, 21, 14 (1995). 

Grote, J. G., Optical interconnects for computer applications, in Tri-Service Photonics Coordinating Committee Proceedings from the DoD Photonics Conference, 1996, p. 253. 

Premises cables are generally deployed to support backbone, horizontal, and interconnect applications. Higher fiber count tight buffered cables discribed later, can be used as intrabuilding backbones that connect a main cross-connect to an entrance facility or intermediate cross-connect. Likewise, lower fiber count cables can link an intermediate cross-connect to a telecommunications room (i.e., horizontal cross-connect) feeding multiple workstations. Simplex and duplex interconnect cables are commonly used to patch the optical signal from end equipment to the hardware containing the main distribution lines, in order to complete the passive optical path. These cables can also provide optical service to workstations, or can connect one patch panel to a second patch panel as in a cross-connect application. 

---