Printed Circuit Design & Fab - February 2008 - (Page 32)

OPTICAL INTERCONNECT OPTOELECTRONICS Comes of Age Optical interconnects are expected to significantly increase computing power in products with ultra-high frequency data rates, increasing its usage over the next 5 years. BY DR. BRUCE L. BOOTH and JACK FISHER Optical interconnections are being considered for use throughout the backplane, in the motherboard, to or from adjoining daughter cards or from any number of associated interposer peripheral boards. Several years back, people were talking about “optical interconnect” and “embedded waveguides” especially in the high-speed industry. Then, improvements in high frequency copper signal transmission changed the market, and the discussion of “opto” declined to almost nothing. Today, implementation of optical interconnection technology is reappearing as a method to resolve or reduce the impact of issues associated with increasingly high frequency data rates beyond 10 GHz and aggregate data rates in the terabit/sec realm. The use of optoelectronics in these applications is expected to significantly increase overall computing power. There are some concerns about the use of copper, particu- FIGURE 1. Self supporting flexible waveguide film. 32 larly for 10 to 20 Gbps or higher products, where EMI can be a problem. This is particularly true in aerospace and military environments. Also, as package density increases, heat dissipation capabilities are reduced, and the costs associated with a copper solution increases exponentially. Even with these high-speed requirements looming large on the horizon, it is anticipated that the widespread commercial implementation of optoelectronic solutions remains at least five years away. For most applications, whether it be telecommunications, computers or data transmissions, there are a broad range of optical capabilities that must become available to facilitate a complete optical interconnection system. The optical capability also needs to be compatible with the complete electronic system to permit the creation of hybrid configurations. Application-driven capabilities, such as on-substrate based waveguides, are optical signal carrying “wires.” They are typically glass fibers that can be incorporated in films and placed either on the surface or embedded, off-substrate such as with a flexible and/or bendable link. The system will also include coupling interfaces and connectivity to light sources and photodetectors. In addition, application specific compatibility and reliability must be met for reasonable manufacturing assembly processes, thermal mechanical environmental impact, and lifetime requirements. Substrate connectivity starts from the backplane or motherboard and continues through to the chip level, typically on or in association with the daughter boards. The signal must also move between chips on multiple boards and ultimately back out off the motherboard. These same optical capabilities are also applicable to stand alone packaged transmitter and receiver applications and for substrate-based or stand alone functional splitters, star couplers or other components providing functionality. The point here being that requirements and capabilities meeting practiFEBRUARY 2008 PRINTED CIRCUIT DESIGN & FAB

Table of Contents Feed for the Digital Edition of Printed Circuit Design & Fab - February 2008

Printed Circuit Design & Fab - February 2008 Contents Our Line Market Watch Around the World Happenings ROI Tip Jar Interconnect Strategies IC/PCB Co-Design Modeling Design Tools Optical Interconnect Trade Shows Laminate Materials Off the Shelf Marketplace Ad Index BGA Bulletin

Printed Circuit Design & Fab - February 2008

For optimal viewing of this digital publication, please enable JavaScript and then refresh the page. If you would like to try to load the digital publication without using Flash Player detection, please click here.